Motor apparatus having improved connector unit

ABSTRACT

A motor apparatus provided with a connector unit ( 40 ) to which an external connector is connected, wherein the connector unit ( 40 ) has a plurality of conductive members ( 64, 65, 66 ) arranged over a base portion ( 50 ) and a connector connecting portion ( 70 ) provided with a plug-in hole in which the external connector is plugged, wherein the conductive members ( 64, 65, 66 ) respectively include connector-side connecting portions ( 64   a,    65   a,    66   a ) connected to the external connector so as to face the connector connecting portion ( 70 ) from a first direction reversed to a plug-in direction of the external connector to the plug-in hole and base-side connecting portions ( 64   b,    65   b,    66   b ) connected to terminals or wirings provided in the base portion ( 50 ), wherein the connector-side connecting portions ( 64   a,    65   a,    66   a ) are respectively inserted into a plurality of insertion holes ( 74, 75, 76 ) provided at positions different from each other in a second direction intersecting the first direction, and wherein the base-side connecting portions ( 64   b,    65   b,    66   b ) are respectively arranged at the same position in the second direction.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/778,764, filed on Sep. 21, 2015, which is the National Stage Filingof PCT Application Serial No. PCT/JP2014/057746, filed on Mar. 20, 2014which claims priority to Japanese Patent Application Serial No.2013-060810 filed on Mar. 22, 2013; Japanese Patent Application SerialNo. 2013-060933, filed on Mar. 22, 2013; Japanese Patent ApplicationSerial No. 2013-072538, filed on Mar. 29, 2013; Japanese PatentApplication Serial No. 2013-167986, filed on Aug. 13, 2013 and JapanesePatent Application Serial No. 2013-167987, filed on Aug. 13, 2013, thecontents of which are incorporated by reference herein.

TECHNICAL FIELD

The present invention relates to a motor apparatus provided with aconnector unit to be connected to an external connector and a motorsection supplied with driving current through the connector unit.

BACKGROUND ART

As one example of a motor apparatus described above, there is a wipermotor for driving a wiper apparatus mounted on such a vehicle as anautomobile. The wiper motor has a motor section provided with anarmature shaft which is rotated when driving current is supplied to themotor section, a reduction gear mechanism section for reducing speed ofrotation of the armature shaft to increase torque, and a connector unitattached to the motor section or the reduction gear mechanism sectionand connected to an external connector, wherein driving current issupplied from the external connector to the motor section through theconnector unit.

One example of a wiper motor having a structure described above isdescribed in Japanese Patent Application Laid-Open Publication No.2008-236995 (FIGS. 11 and 12). The wiper motor described in JapanesePatent Application Laid-Open Publication No. 2008-236995 (FIGS. 11 and12) has a motor subassembly (the motor section) provided with anarmature shaft (armature spindle), a reduction gear portion subassembly(the reduction gear mechanism section) provided with a reduction gearmechanism including a worm and a worm wheel, and a brush holder unit(the connector unit) disposed between the motor subassembly and thereduction gear portion subassembly and provided with a connector boxconnected to an external connector.

The brush holder constituting the brush holder unit is formed of a resinmaterial having electrical insulation, and is molded into apredetermined shape by injection molding. Furthermore, a plurality ofinternal wirings is embedded in the brush holder by insert molding. Therespective internal wirings which are insert members are strip-shapedelectrical conductive members bent in an X-axis direction, a Y-axisdirection, and Z-axis direction. That is, the respective internalwirings have a labyrinth-like shape. The respective internal wirings areembedded in the brush holder such that they do not interfere with oneanother. One end sides of the respective internal wirings are drawn intothe motor section and the reduction gear mechanism section, while theother end sides thereof are drawn into the connector box to be collectedtherein.

SUMMARY

In the wiper motor described in Japanese Patent Application Laid-OpenPublication No. 2008-236995 (FIGS. 11 and 12), a plurality of internalwirings (electrical conductive members) bent in a three-dimensionalfashion are embedded into the brush holder by the insert molding.Therefore, in order to mold the brush holder, a plurality of slidingmolds was required in addition to an upper mold and a lower mold. Thatis, it was necessary to undergo a complicated manufacturing process inorder to the wiper motor described in Japanese Patent ApplicationLaid-Open Publication No. 2008-236995 (FIGS. 11 and 12).

It is therefore an object of the present invention to simplify amanufacturing process of a motor apparatus including a wiper motor asmuch as possible.

A motor apparatus according to the present invention is provided with aconnector unit to which an external connector for supplying drivingcurrent to a motor section is connected, wherein the connector unitcomprises: a base portion provided with an opening portion in which anarmature shaft extending from the motor section is inserted; a connectorconnecting portion provided with a plug-in hole in which the externalconnector is plugged; and a plurality of conductive members arrangedover the base portion and the connector connecting portion, wherein theconductive members respectively include connector-side connectingportions connected to the external connector so as to face the connectorconnecting portion from a first direction reversed to a plug-indirection of the external connector to the plug-in hole and base-sideconnecting portions connected to terminals or wirings provided in thebase portion, wherein the connector-side connecting portions of therespective conductive members are respectively inserted into a pluralityof insertion holes provided at positions different from each other in asecond direction intersecting the first direction, and wherein thebase-side connecting portions of the conductive members are respectivelyarranged at the same position in the second direction.

In accordance with one aspect of the present invention, a holder memberholding the conductive members is provided between the same and theconnector connecting portion so as to face from the first direction tothe connector connecting portion.

In accordance with another aspect of the present invention, aninsulating projection interposed between the conductive members adjacentto each other is formed on an inner face of the holder member facing theconnector connecting portion.

In accordance with still another aspect of the present invention, theconnector unit is at least provided with a first attaching portionattached with a first conductive member and a second attaching portionattached with a second conducive member, the first attaching portion hasa first supporting face on which a lower face of the first conductivemember is placed, and a first positioning face rising from the firstsupporting face, on which a side face of the first conductive member iscaused to abut, and the second attaching portion has a second supportingface extending from the first positioning face in parallel with thefirst supporting face, on which a lower face of the second conductivemember is placed, and a second positioning face rising from the secondsupporting face, on which a side face of the second conductive member iscaused to abut.

In accordance with yet another aspect of the present invention, theconductive members respectively have intermediate portions connectingthe connector-side connecting portions and the base-side connectingportions, the intermediate portions including flat portions parallel tothe base-side connecting portions, and the flat portions of theconductive members are respectively arranged at positions different fromone another in the second direction.

According to the present invention, a simplified manufacturing processof a motor apparatus including a wiper motor is realized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a wiper motor;

FIG. 2 is a perspective view of a connector unit shown in FIG. 1;

FIG. 3 is a plan view of the connector unit shown in FIG. 1;

FIG. 4 is an arrow view from “A” in FIG. 3;

FIG. 5 is an arrow view from “B” in FIG. 3;

FIG. 6 is a perspective view showing positions of electrical components;

FIG. 7 is a perspective view showing an attached conductive plate;

FIG. 8 is another perspective view showing the attached conductiveplate;

FIG. 9 is an exploded perspective view showing the attached conductiveplate and a holder member;

FIG. 10 is a sectional view showing the attached conductive plate;

FIG. 11 is a perspective view of the holder member;

FIG. 12a is a partially-omitted bottom view of a connector unit;

FIG. 12b is an explanatory view showing a section taken along line A-Ain FIG. 12 a;

FIG. 13a is a partially-omitted side view of the connector unit;

FIG. 13b is an explanatory view showing a section taken along line B-Bin FIG. 13 a;

FIG. 14 is a plan view of a wiper motor according to a secondembodiment;

FIG. 15 is a partially-sectional view taken along line A-A in FIG. 14;

FIG. 16 is a view of a connector unit and a worm wheel as viewed from aback side in FIG. 14;

FIG. 17 is a perspective view of the connector unit as viewed from theside of a reduction gear mechanism section;

FIG. 18 is a partially-enlarged view comparing a switching plate of thesecond embodiment and a switching plate of a comparative example;

FIG. 19 is a plan view showing a reduction gear mechanism section of awiper motor according to a third embodiment;

FIG. 20 is a plan view of a wiper motor according to a fourthembodiment;

FIG. 21 is a partially-sectional view taken along line A-A I FIG. 20;

FIG. 22 is a perspective view of a worm wheel component as viewed from asurface side;

FIG. 23 is a perspective view of the worm wheel component as viewed froma back side;

FIG. 24 is a partially-enlarged view for explaining a positionalrelationship of a coupling portion, a recessed portion close to a gearportion, and a recessed portion close to a wheel shaft fixing hole;

FIG. 25 is an explanatory view for explaining a size relationship of afirst cylindrical portion, a second cylindrical portion, and therecessed portion close to the gear portion;

FIG. 26 is a view of a connector unit and a worm wheel as viewed from aback side in FIG. 20;

FIG. 27 is a plan view showing a reduction gear mechanism section of awiper motor according to a fifth embodiment;

FIG. 28 is a plan view of an electric motor apparatus 301 according to asixth embodiment;

FIG. 29 is a view showing a sleeve 330;

FIG. 30 is a perspective view of a resin-made bush 340;

FIG. 31 is a view showing a whirl-stop mechanism for the resin-made bush340;

FIG. 32 is a view showing a shaft abutting portion 325;

FIG. 33 is a view showing a first modified example (a shaft abuttingportion 326) of the shaft abutting portion;

FIG. 34 is a view showing a second modified example (a shaft abuttingportion 327) of the shaft abutting portion;

FIG. 35 is a view showing a third modified example (a shaft abuttingportion 328) of the shaft abutting portion;

FIG. 36 is a view showing a modified example (a transmission mechanism3150) of the transmission mechanism;

FIG. 37 is a plan view of an electric motor apparatus 401 according to aseventh embodiment;

FIG. 38 is a sectional view of a transmission mechanism 450;

FIG. 39 is a view showing a coupling plate 457 and a second sector gear458;

FIG. 40 is a plan view showing a modified example (a transmissionmechanism 4150) of the transmission mechanism;

FIG. 41 is a sectional view of the transmission mechanism 4150; and

FIG. 42 is a view showing a recessed portion 456 g of a powertransmission member 456.

DETAILED DESCRIPTION First Embodiment

Hereinafter, a first embodiment of the present invention will bedescribed in detail with reference to the drawings. A wiper motor 10shown in FIG. 1 is a motor apparatus which is used as a driving sourceof a rear wiper apparatus mounted on a rear hatch of a vehicle or thelike, and provided with a motor section 20 and a reduction gearmechanism section 30.

The motor section 20 is composed of a four-pole motor with brush, andprovided with a yoke 21 as a casing formed of a magnetic steel plate.The yoke 21 is formed into a bottomed cylindrical shape by press work,and four magnets 22 are fixed to an inner circumferential face of theyoke 21. However, only two magnets 22 are shown in FIG. 1. An armature23 is rotatably accommodated and surrounded by these magnets 22 via apredetermined gap (air gap) between the armature 22 and each magnet 22.

The armature 23 is provided with an armature shaft rotatably supportedby the yoke 21, and a commutator 25 and an armature core 26 are fixed tothe armature shaft 24. The commutator 25 is provided with a plurality ofsegments, and a plurality of armature coils are wounded on the armatureshaft 24. Furthermore, a coil end of each armature coil is electricallyconnected to each segment of the commutator 25.

A power-supply unit 27 provided with a plurality of brushes coming insliding contact with the commutator 25 is arranged inside a gear case 31around the commutator 25. The power-supply unit 27 is supplied withdriving current via a connector unit 40 integrated with the reductiongear mechanism section 30. The driving current supplied to thepower-supply unit 27 is supplied to the armature 23 (each armature coil)via the brushes and commutator 25. When the driving current is suppliedto the armature 23, the armature shaft 24 is rotated in a predetermineddirection at a predetermined velocity.

The reduction gear mechanism section 30 is provided with the gear case31 forged from aluminum material and serving as a casing. A reductiongear mechanism accommodating portion 31 a and a connector unitaccommodating portion 31 b which are molded into a bathtub shape areprovided inside the gear case 31. The gear case 31 is fixed to anopening end of the yoke 21 by two fixing screws “S”.

One end of the armature shaft 24 projecting from the opening end of theyoke 21 extends through the connector unit accommodating portion 31 b toadvance into the reduction gear mechanism accommodating portion 31 a.The one end of the armature shaft 24 advancing into the reduction gearmechanism portion 31 a is coupled to one end of a worm shaft 32rotatably supported within the reduction gear mechanism accommodatingportion 31 a.

A worm wheel 33 is accommodated in the reduction gear mechanismaccommodating portion 31 a. The worm wheel 33 is rotatably supported bya supporting shaft 34, and a teeth portion of the worm wheel 33 mesheswith a worm formed integrally with the worm shaft 32. A reduction gearmechanism for reducing rotation of the armature shaft 24 to increasetorque is constituted by the worm shaft 32 and the worm wheel 33 thusconfigured.

Furthermore, a power converting mechanism 35 converting a rotatingmotion of the worm wheel 33 to a swinging motion is accommodated in thereduction gear mechanism accommodating portion 31 a. The powerconverting mechanism 35 is provided with an arm member 36 a whose oneend is rotatably coupled to the worm wheel 33 and an arm member 36 bwhose one end is fixed to an output shaft 37, and the other ends of thearm member 36 a and the arm member 36 b are rotatably coupled to eachother by a coupling pin 38.

The output shaft 37 is rotatably attached to the gear case 31, and arear wiper arm for wiping a rear window glass is fixed to an end portionof the output shaft 37 projecting outside the gear case 31.

When the armature shaft 24 of the motor section 20 is rotated, therotation is reduced by the reduction gear mechanism (the worm shaft 32and the worm wheel 33), so that torque is increased. Furthermore, therotating motion of the worm wheel 33 is converted into a swinging motionby the power converting mechanism 35 to be transmitted to the outputshaft 37. Thereby, the rear wiper arm fixed to the output shaft 37 isswung (reciprocated) on the rear window glass, so that the rear windowglass is wiped.

A connector unit 40 shown in FIG. 2 to FIG. 5 is accommodated in theconnector case accommodating portion 31 b of the gear case 31. Theconnector unit 40 is arranged inside the connector unit accommodatingportion 31 b shown in FIG. 1, and it is provided with a base portion 50arranged within the connector unit accommodating portion 31 b shown inFIG. 1 and covered with a cover (not shown) fixed to the gear case 31, aplurality of electrical components 60 (half-tone dotted meshing portionsin the figures), and a connector connecting portion 70 which is notcovered with the cover and is exposed outside.

The base portion 50 and the connector connecting portion 70 are composedof an integral resin member injection-molded, and an external connector(not shown) where a plurality of wirings connected to a vehicle-mountedbattery, a vehicle-mounted controller, and the like are collected isconnected to the connector connecting portion 70. The electricalcomponents 60 are formed of a steel material or a steel plate havingconductivity. Furthermore, the electrical components 60 includeelectronic parts (for example, a varistor) for removing brush noises,and the like.

As shown in FIG. 2 to FIG. 5, the base portion 50 is formed into anapproximately flat plate shape, and a circular opening portion 51through which the armature shaft 24 (FIG. 1) is extended is providedwith at an approximately central portion of the base portion 50 in alongitudinal direction of the base portion 50. Three contact plateattaching portions 52 a to 52 c are formed on one end side of the baseportion 50 in the longitudinal direction (the right side on the sheetshowing FIG. 2, and the upper sides on the sheets showing FIG. 3 to FIG.5), and contact plates 61 a to 61 c are attached to the respectivecontact plate attaching portions 52 a to 52 c, respectively. The contactplate attaching portions 52 b and 52 c of three contact plates attachingportions 52 a to 52 c are formed into a groove shape, and the contactplates 61 b and 61 c are fitted inside these contact plate attachingportions 52 b and 52 c, respectively. Incidentally, as shown in FIG. 6,retaining pieces 62 are properly formed on the respective contact plates61 a to 61 c. On the other hand, as shown in FIGS. 4 and 5, retainingprojections 53 engaged with the retaining pieces 62 formed on therespective contact plates 61 a to 61 c to prevent the contact plates 61a to 61 c from falling off are properly formed on the respective contactplate attaching portions 52 a to 52 c.

As shown in FIGS. 4 and 5, connecting spaces (welding spaces) CS1 andCS2 are provided in the contact plate attaching portions 52 b and 52 c,respectively. At an assembling time of the connector unit 40, electricalconnections between the contact plates 61 b and 61 d and jumper wires 63b and 63 c (FIGS. 4 and 6) are performed in the connecting spaces CS1and CS2, respectively.

Here, the contact plates 61 a to 61 c are ones obtained by bending thinplates made of brass material excellent in conductivity in apredetermined shape. The shapes of the contact plates 61 a to 61 c areshown most clearly in FIG. 6. One end sides of the contact plates 61 ato 61 c constitute sliding contact arm portions coming in slidingcontact with switching plates (not shown) attached to the worm wheel 33.The respective sliding contact arm portions of the contact plates 61 ato 61 c slide on the switching plates according to rotation of the wormwheel 33 to perform switching actions. Thereby, when a wiper switch isturned OFF, the rear wiper arm is automatically stopped on the rearwindow glass at a predetermined stop position.

FIG. 2 is referred to again. A connector connecting portion 70 is formedon the opposite side (a left side on the sheet showing FIG. 2, and lowersides on the sheets showing FIG. 3 to FIG. 5) to the contact platesattaching portions 52 a to 52 c through the opening portion 51. As shownin FIG. 3, a plug-in hole 71 in which an external connector (not shown)is plugged is provided on one side of the connector connecting portion70. The external connector is plugged in the plug-in hole 71 from thenear side of the sheet showing FIG. 3 in FIG. 3 to the depth sidethereof in FIG. 3, from the right side from the left side toward theleft side on the sheet showing FIG. 4 in FIG. 4, and from the left sidetoward the right side on the sheet showing FIG. 5 in FIG. 5. That is,the directions of arrows X shown in FIG. 2, FIGS. 4 and 5 are in theplug-in direction of the external connector to the plug-in hole 71.

As shown in FIGS. 7 and 8, a plurality of conductive members arearranged over the connector connecting portion 70 and the base portion50 in the connector unit 40. Specifically, a first conductive plate 64serving as a first conductive member, a second conductive plate 65serving as a second conductive member, and a third conductive plate 66serving as a third conductive member are arranged.

As shown in FIG. 9, the first conductive plate 64, the second conductiveplate 65, and the third conductive plate 66 are attached to theconnector attaching portion 70 from a first direction (direction ofarrow Y) reverse to the plug-in direction (direction of arrow X) intothe plug-in hole 71 (FIG. 3) for the external connector to the connectorconnecting portion 70. That is, an attaching direction of threeconductive plates 64, 65 and 66 to the connector connecting portion 70is exactly opposed to the attaching direction (connecting direction) ofthe external connector to the connector connecting portion 70.Furthermore, all of three conductive plates 64, 65 and 66 are attachedto the connector connecting portion 70 from the same direction. Anattaching structure of the first conductive plate 64, the secondconductive plate 65, and the third conductive plate 66 to the connectorconnecting portion 70 will be specifically described below.

As shown in FIGS. 3 and 9, three insertion holes 74, 75 and 76 areformed in a bottom portion of the plug-in hole 71 (FIG. 3) in which theexternal connector is plugged in a row along a second direction (adirection of arrow Z) crossing the first direction (the direction ofarrow Y). That is, the three insertion holes 74, 75 and 76 are providedat different positions from one another in the second direction (thedirection of arrow Z).

On the other hand, as shown in FIGS. 6 and 9, the respective conductiveplates 64, 65, and 66 are inserted into the insertion holes 74, 75 and76, respectively, and they have connector-side connecting portions 64 a,65 a, and 66 a electrically connected to the external connector pluggedin the plug-in hole 71 (FIG. 3), base-side connecting portions 64 b, 65b, and 66 b connected to terminals or wirings provided in the baseportion 50, and intermediate portions 64 c, 65 c, and 66 c connectingthe connector-side connecting portions 64 a, 65 a, and 66 a and thebase-side connecting portions 64 b, 65 b, and 66 b with each other. Ofcourse, the connector-side connecting portion, the base-side connectingportion, and the intermediate portion of each conductive plate 64, 65,66 are formed in an integral manner. That is, the above discriminationis a discrimination for convenience of explanation.

As shown in FIG. 9, the connector-side connecting portion 64 a of thefirst conductive plate 64 is inserted into the insertion hole 74 alongthe first direction (the direction of arrow Y) to project into theplug-in hole 71 (FIG. 3). The connector-side connecting portion 65 a ofthe second conductive plate 65 is inserted into the insertion hole 75along the first direction (the direction of arrow Y) to project into theplug-in hole 71 (FIG. 3). The connector-side connecting portion 66 a ofthe second conductive plate 66 is inserted into the insertion hole 76along the first direction (the direction of arrow Y) to project into theplug-in hole 71 (FIG. 3). Each connector-side connecting portion 64 a,65 a, 66 a of each conductive plate 64, 65, 66 projecting in the plug-inhole 71 comes in contact with a predetermined terminal of the externalconnector plugged in the plug-in hole 71, namely, connected to theconnector unit 40 to be electrically connected to the predeterminedterminal. Specifically, the connector-side connecting portion 64 a ofthe first conductive plate 64 and the connector-side connecting portion65 a of the second conductive plate 65 are electrically connected todrive-line terminals of the external connector, respectively.Furthermore, the connector-side connecting portion 66 a of the thirdconductive plate 66 is electrically connected to a control-line terminalof the external connector. That is, the first conductive plate 64 andthe second conductive plate 65 are conductive members of the drive line,while the third conductive plate 66 is a conductive member of thecontrol line.

As shown in FIGS. 5 and 7, the base-side connecting portion 64 b of thefirst conductive plate 64 is connected to a female-type terminal 67which is one of terminals provided in the base portion 50, and it iselectrically connected to the power-supply unit (FIG. 1) via thefemale-type terminal. Furthermore, as shown in FIG. 4, the base-sideconnecting portion 64 b of the first conductive plate 64 is alsoconnected to a jumper wire 63 c which is one of the wirings provided inthe base portion 50, and it is electrically connected to the contactplate 61 c via the jumper wire 63 c.

As shown in FIGS. 5 and 7, the base-side connecting portion 65 b of thesecond conductive plate 65 is connected to a female-type terminal 68which is another of the terminals provided in the base portion 50 and itis electrically connected to the power-supply unit (FIG. 1) via thefemale-type terminal 68.

As shown in FIG. 4, the base-side connecting portion 66 b of the thirdconductive plate 66 is connected to a jumper wire 63 b which is anotherof the terminal provided in the base portion 50, and it is electricallyconnected to the contact plate 61 b via the jumper wire 63 b.Incidentally, the contact plate 61 a is not connected to any of theconductive plates.

The jumper wires 63 b and 63 c are ones obtained by bending conductivewires with a predetermined length which is circular in section so as toextend along jumper wire attaching grooves formed in the base portion50. The jumper wire attaching groove is formed with a plurality ofcatching claws properly, and the jumper wires 63 b and 63 c attached tothe jumper wire attaching grooves are held by the catching claws atplurality of portions in the longitudinal directions thereof.

As shown in FIG. 9, a first attaching portion 81, a second attachingportion 82, a third attaching portion 83 on which one portions of theintermediate portions 64 c, 65 c and 66 c of the respective conductiveplates 64, 65 and 66 are placed, respectively, are formed in a steppedfashion on a side face of the connector connecting portion 70 and a sideface of the base portion 50 continuous thereon. Here, flat portions 64 c1, 65 c 1 and 66 c 1 parallel to the base-side connecting portions 64 b,65 b and 66 b are included in the intermediate portions 64 c, 65 c and66 c of the respective conductive plates 64, 65 and 66, respectively(see FIG. 9 in conjunction with FIG. 6). As shown in FIGS. 7 and 8, theflat portion 64 c 1 of the intermediate portion 64 c of the firstconductive plate 64 is placed on the first attaching portion 81, theflat portion 65 c 1 of the intermediate portion 65 c of the secondconductive plate 65 is placed on the second attaching portion 82, andthe flat portion 66 c 1 of the intermediate portion 66 c of the thirdconductive plate 66 is placed on the third attaching portion 83,respectively.

As shown in FIG. 9, the first attaching portion 81 is composed of afirst supporting face 81 a on which a lower face of the flat portion 64c 1 is placed, and a first positioning face 81 b which rises from anedge of the first supporting face 81 a and on which a side face of theflat portion 64 c 1 is caused to abut.

The second attaching portion 82 is composed of a second supporting face82 a on which a lower face of the flat portion 65 c 1 is placed, and asecond positioning face 82 b which rises from an edge of the secondsupporting face 82 a and on which a side face of the flat portion 65 c 1is caused to abut.

The third attaching portion 83 is composed of a third supporting face 83a on which a lower face of the flat portion 66 c 1 is placed, and athird positioning face 83 b which rises from an edge of the thirdsupporting face 83 a and on which a side face of the flat portion 66 c 1is caused to abut.

Here, the second supporting face 82 a of the second attaching portion 82extends from the edge of the first positioning face 81 b of the firstattaching portion 81 in parallel with the first supporting face 81 a.Furthermore, the third supporting face 83 a of the third attachingportion 83 extends from the edge of the second positioning face 82 b ofthe second attaching portion 82 in parallel with the second supportingface 82 a. That is, the first attaching portion 81, the second attachingportion 82 and the third attaching portion 83 are formed in a steppedfashion along the second direction (the direction of arrow Z).

As shown in FIG. 10, therefore, the flat portion 64 c 1 of the firstconductive plate 64 placed on the first attaching portion 81 (the firstsupporting face 81 a), the second portion 65 c 1 of the secondconductive plate 65 placed on the second attaching portion 82 (thesecond supporting face 82 a), and the flat portion 66 c 1 of the thirdconductive plate 66 placed on the third attaching portion 83 (the thirdsupporting face 83 a) are arranged at positions different from oneanother in the second direction (the direction of arrow Z). On the otherhand, the base-side connecting portions 64 b, 65 b and 66 b of therespective conductive plates 64, 65 and 66 are arranged at the sameposition in the second direction (the direction of arrow Z). In otherwords, the flat portions 64 c 1, 65 c 1 and 66 c 1 are arranged atheights different from one another on the sheet showing FIG. 10, whilethe base-side connecting portions 64 b, 65 b and 66 c are arranged atthe same height. Incidentally, in FIG. 10, hatchings are attached to therespective conductive plates 64, 65 and 66 in order to clarifyboundaries of the respective conductive plates 64, 65 and 66, but thesehatchings do not show sections. Furthermore, arrangement situations ofthe respective conductive plates 64, 65 and 66 are further clearlyunderstood by referring to FIG. 10 in conjunction with FIGS. 7 and 8.

As shown in FIG. 2, a holder member 90 is attached to the connectorconnecting portion 70 of the connector unit 40. As shown in FIG. 9, theholder member 90 is attached to the connector attaching portion 70 fromthe first direction (the direction of arrow Y) toward a bottom portionouter face (a bottom face of the connector connecting portion 70) of theplug-in hole 71 (FIG. 3) in which the external connector is plugged.That is, the holder member 90 is attached to the connector connectingportion 70 from the same direction as the conductive plates 64, 65 and66 toward the connector connecting portion 70. The conductive plates 64,65 and 66 are held by the connector connecting portion 70 and the holdermember 90 attached to the connector connecting portion 70 in asandwiching fashion.

As shown in FIG. 11, the holder member 90 is provided with a main wallportion 91 facing the bottom face of the connector connecting portion 70and a side wall portion 92 extending from one end of the main wallportion 91 in a longitudinal direction in a direction approximatelyorthogonal to the main wall portion 91. Three engagement claws 93 whichare inserted into three engagement holes 77 (FIG. 9) provided in thebottom face of the connector connecting portion 70, respectively, areformed on an inner face of the main wall portion 91 integrally with themain wall portion 91. Furthermore, a plug-in projection 94 inserted intoa through-hole 78 (FIG. 9) provided in the bottom face of the connectorconnecting portion 70 is formed on the inner face of the main wallportion 91 integrally with the main wall portion 91. The threeengagement claws 93 penetrate predetermined through-holes 77 to advanceinside the plug-in hole 71 (FIG. 3) and engage peripheries of therespective engagement holes 77. Thereby, the holder member 90 issecurely fixed to an exact position on the connector connecting portion70. As a result, the conductive plates 64, 65 and 66 held between theconnector connecting portion 70 and the holder member 90 are alsosecurely fixed to exact positions. In other words, falling-out orpositional displacement of the conductive plates 64, 65 and 66 and theholder member 90 is securely prevented.

Furthermore, an insulating projection 95 with a predetermined shape isintegrally formed on an inner face of the main wall portion 91 of theholder member 90. As shown in FIGS. 7 and 8, when the holder member 90is attached to the connector connecting portion 70 which has beenattached with the conductive plates 64, 65 and 66, the insulatingprojection 95 provided on the holder member 90 advances between thefirst conductive plate 64 and the second conductive plate 65 adjacent toeach other to be interposed therebetween, as shown in FIGS. 12(a) and12(b). Thereby, insulation between the first conductive plate 64 and thesecond conductive plate 65 is secured more securely. Furthermore, asshown in FIGS. 13(a) and 13(b), the side wall portion 92 of the holdermember 90 is formed in a stepped fashion corresponding to the firstattaching portion 81, the second attaching portion 82 and the thirdattaching portion 83 formed in the stepped fashion. Thereby, since theside wall portion 92 of the holder member 90 is arranged along the flatportion 64 c 1 of the first conductive plate 64, the flat portion 65 c 1of the second conductive plate 65, and the flat portion 66 c 1 of thethird conductive portion 66 arranged at the different positions fromeach other in the second direction (the direction of arrow Z),respectively, insulation between the conductive plates adjacent to eachother is secured more securely.

Next, an attaching step to the first conductive plate 64, the secondconductive plate 65 and the third conductive plate 66 to the connectorconnecting portion 70 of the manufacturing steps of the wiper motor 10having the above structure will be described. As described above, all ofthe first conductive plate 64, the second conductive plate 65 and thethird conductive plate 66 are attached to the connector connectingportion 70 from the same direction (the first direction/the direction ofarrow Y) toward the connector connecting portion 70 (see FIG. 9).Furthermore, the respective base-side connecting portions 64 b, 65 b and66 b of the first conductive plate 64, the second conductive plate 65and the third conductive plate 66 are arranged at the same position toone another in the second direction (the direction of arrow Z)orthogonal to the first direction (the direction of arrow Y) in a statewhere these conductive plates 64, 65 and 66 have been attached to theconnector connecting portion 70. Thereby, the three conductive plates64, 65 and 66 are attached to the connector connecting portion 70 in theorder from the conductive plate arranged in the deepest position. Thatis, as shown in FIG. 9, the third conductive plate 66 is first attached,and the second conductive plate 65 and the first conductive plate 64 arethen performed in this order. Specifically, the connector-sideconnecting portion 66 a of the third conductive plate 66 is insertedinto the insertion hole 76 provided in the connector connecting portion70. At this time, the connector-side connecting portion 66 a of thethird conductive plate 66 is inserted into the insertion hole 76 until aportion (the flat portion 66 c 1) of the intermediate portion 66 c abutson the third positioning face 83 b of the third attaching portion 83.That is, positioning of the third conductive plate 66 is performed bythe third positioning face 83 b of the third attaching portion 83.Incidentally, another portion of the intermediate portion 66 c of thethird conductive plate 66 is fitted in the holding groove 79 formedalong an arrangement direction of the insertion holes 74, 75 and 76.

Next, the connector-side connecting portion 65 a of the secondconductive plate 65 is inserted into the insertion hole 75 provided inthe connector connecting portion 70. At this time, the connector-sideconnecting portion 65 a of the second conductive plate 65 is insertedinto the insertion hole 75 until a portion (the flat portion 65 c 1) ofthe intermediate portion 65 c abuts on the second positioning face 82 bof the second attaching portion 82. That is, positioning of the secondconductive plate 65 is performed by the second positioning face 82 b ofthe second attaching portion 82.

Thereafter, the connector-side connecting portion 64 a of the firstconductive plate 64 is inserted into the insertion hole 74 provided inthe connector connecting portion 70. At this time, the connector-sideconnecting portion 64 a of the first conductive plate 64 is insertedinto the insertion hole 74 until a portion (the flat portion 64 c 1) ofthe intermediate portion 64 c abuts on the first positioning face 81 bof the first attaching portion 81. That is, positioning of the firstconductive plate 64 is performed by the first positioning face 81 b ofthe first attaching portion 81.

As described above, by attaching the first conductive plate 64, thesecond conductive plate 65 and the third conductive plate 66 in apredetermined order, all of the conductive plates 64, 65 and 66 areattached to the connector connecting portion 70 in the same direction(the first direction/the direction of arrow Y). That is, since all ofthe plurality of conductive plates 64, 65 and 66 bent in athree-dimensional fashion are attached to the connector connectingportion 70 without utilizing insert molding and all of the plurality ofconductive plates 64, 65 and 66 are attached to the connector connectingportion 70 from the same direction, the attaching step (assembling step)of the conductive plates 64, 65 and 66 is simplified. Furthermore, sincethe positioning faces 81 b, 82 b and 83 b corresponding to therespective conductive plates 64, 65 and 66 are prepared, respectively,assemblability of the conductive plates 64, 65 and 66 is improved.

The holder member 90 is attached to the connector connecting portion 70which has been attached with the conductive plates 64, 65 and 66 in theabove manner. The holder member 90 is attached to the connectorconnecting portion 70 from the same direction as the attaching directionof the conductive plates 64, 65 and 66 to the connector connectingportion 70, namely, the first direction (the direction of arrow Y)toward the connector connecting portion 70. That is, all of theplurality of conductive plates 64, 65 and 66 and the holder member 90are attached to the connector attaching portion 70 from the samedirection. Therefore, the attaching step (assembling step) of theconductive plates 64, 65 and 66 and the holder member 90 to theconnector connecting portion 70 is simplified, which results inrealization of simplification of the manufacturing steps of the wipermotor 10, size reduction of the wiper motor 10, and the like.Furthermore, since attaching directions of the plurality of conductiveplates 64, 65 and 66 and the holder member 90 are the same, automationof the assembling steps of the conductive plates 64, 65 and 66 and theholder member 90 becomes easy.

The present invention is not limited to the above embodiment, but it canbe variously modified without departing from the scope of the presentinvention. For example, in the above embodiment, since the connectorunit accommodating portion in which the connector unit is accommodatedis provided in the gear case, but the connector unit accommodatingportion may be provided at the opening end of the yoke and the connectorunit, and accommodated in the connector unit accommodating portion.

Furthermore, the number of conductive members is not limited to three,but a necessary number of conductive members can be provided accordingto the specification of the motor apparatus (functions). When the numberof conductive members is increased, the number of insertion holes andthe number of attaching portions, provided in the connector connectingportion, are also increased properly in response to the number ofconductive members.

The present invention can be applied to not only the rear wiper but alsoa drive source of a front wiper apparatus of a vehicle or a drive sourceof another apparatus other than the wiper apparatus.

Second Embodiment

Hereinafter, a second embodiment of the present invention will bedescribed in detail with reference to the drawings.

FIG. 14 shows a plan view of a wiper motor according to the secondembodiment, FIG. 15 shows a partially-sectional view taken along lineA-A in FIG. 14, FIG. 16 is a view of a connector unit and a worm wheelas viewed from the back side of FIG. 14, FIG. 17 shows a perspectiveview of the connector unit as viewed from the side of a reduction gearmechanism, and FIG. 18 shows a partially-enlarged view of comparison ofa switching plate of the second embodiment and a switching plate of acomparative example.

As shown in FIG. 14, a wiper apparatus 110 as motor apparatus is used asa drive source of a rear wiper apparatus (not shown) mounted on a rearhatch of a vehicle, and provided with a motor section 120 and areduction gear mechanism section 130. The motor section 120 and thereduction gear mechanism section 130 are integrally coupled to eachother by a pair of fastening screws 111. The wiper motor 110 is arrangedin a narrow space such as a rear hatch, and configured to cause a wiperblade (not shown) provided on a rear glass (not shown) to perform areciprocating wiping action (swinging drive) within a predeterminedangular range.

As shown in FIGS. 14 and 15, the motor section 120 is constituted as afour-pole motor with brush. The motor section 120 is provided with amotor case 121 and the motor case 121 is formed into a bottomedcylindrical shape by performing deep drawing work to a steel plate whichis a magnetic body. The motor case 121 is provided with a pair ofarc-shaped portions 121 a and a pair of straight portions 121 b, and therespective arc-shaped portions 121 a and the respective straightportions 121 b are arranged so as to face each other via a shaft center(an armature shaft 124) of the motor case 121, respectively. Thereby, across-sectional shape of the motor case 121 is formed into anapproximately oval shape. Therefore, thinning can be achieved by savinga widthwise size of the motor case 121, namely, a thickness size in acrosswise direction in FIG. 15.

The respective arc-shaped portions 121 a and the respective straightportions 121 b extend from an opening portion side of the motor case 121to a bottom portion side thereof. Thereby, the motor case 121 is formedinto a straight shape which does not include any stepped portion, whichresults in improvement of ease of the deep drawing work of the motorcase 121. Furthermore, as shown in FIG. 14, since a brush holder 170does not enter the opening portion side of the motor case 121, a lengthof the motor case 121 in an axial direction is also suppressed. Thus,the motor case 121 is formed into an advantageous shape regardingimprovement of moldability, and size reduction and weight reduction.

A total of four magnets 122 formed into an approximately arc shape insection are attached inside the motor case 121. The respective magnets122 are ferrite magnets, for example, and they are fixed along acircumferential direction of the motor case 121 at equal intervals (atintervals of 90 degrees) and an armature 123 is rotatably accommodatedin the respective magnets 122 with a predetermined gap. A base end sideof an armature shaft (rotation shaft) 124 penetrates a rotation centerof the armature 123 to be fixed thereto.

A commutator 125 is fixed to an approximately central portion of thearmature shaft 124 along an axial direction thereof, and the commutator125 is provided with ten segments 125 a. Furthermore, an armature core126 forming the armature 123 is fixed on the side of a base end of thearmature shaft 124, and the armature core 126 is provided with ten teeth126 a. Slots are formed among the respective teeth 126 a. A plurality ofarmature coils 126 a is wound on the respective teeth 126 a by apredetermining winding method with a predetermined number of turns. Coilends of the armature coils 126 b are respectively electrically connectedto the segments 125 a.

A plurality of current-feeding brushes 125 b (only one is shown in FIG.14) comes in sliding contact with each segment 125 a of the commutator125. Each power-supply brush 125 b is movably provided on the brushholder 170 accommodated in the brush holder accommodating portion 134 ofthe housing 131. Driving current from the connector unit 150 is suppliedto each power-supply brush 125 b. Thus, the motor section 120 and theconnector unit 150 are electrically connected via each power-supplybrush 125 b, the commutator 125 and the armature coil 126 b, so thatelectromagnetic force is generated in the armature coil 126 b and thearmature 123 (the armature shaft 124) is rotated. Incidentally, in FIG.15, illustration of each power-supply brush 125 b and the brush holder170 is omitted for convenience of explanation.

The base end side of the armature shaft 124 is rotatably accommodated inthe motor case 121, and it is supported by only a radial bearing 127provided on the bottom portion side of the motor case 121. A thrustbearing supporting the armature shaft 124 from its axial direction isnot provided between the base end side of the armature shaft 124 and themotor case 121. Here, the radial bearing 127 is formed into anapproximately cylindrical shape from, for example, a sintered material,so that the radial bearing 127 is provided with low noise, impactresistance, and self-lubrication and it is hard to generate frictionpowder. However, the radial bearing 127 may also be formed of a plasticmaterial excellent in heat resistance or the like instead of thesintered material.

A worm gear 124 a (not shown in detail) is integrally provided at adistal end side of the armature shaft 124, and the worm gear 124 a isrotated within the housing 131 according to rotation of the armatureshaft 124. The worm gear 124 a is formed into a spiral shape, and it iscaused to mesh with gear teeth 132 a of the worm wheel 132. Here, theworm gear 124 a and the worm wheel 132 constitute a reduction gearmechanism in the present invention. The worm wheel 132 is rotated in astate speed-reduced from rotation speed of the worm gear 124 a accordingto rotation of the worm gear 124 a to reduce rotation speed and outputrotation with elevated torque to the output.

An inner wheel member 128 a of a ball bearing 128 is fixed between thearmature 123 and the worm gear 124 a of the armature shaft 124 bypress-fitting. Furthermore, an outer wheel member 128 b of the ballbearing 128 is held between the housing 131 and a stopper plate 160.Thereby, the armature shaft 124 is rotatably supported by the ballbearing 128 and it is restricted regarding movements in an axialdirection and in a radial direction thereof to the housing 131. Thus,the ball bearing 128 is provided with functions serving as a radialbearing and as a thrust bearing. Therefore, a thrust bearing supportingthe armature shaft 124 from the axial direction of the armature shaft124 is not also provided between the distal end side of the armatureshaft 124 and the housing 131.

Here, since the wiper motor 110 is constituted as a four-pole motorsize-reduced and weight-reduced, for example, it is more in calorificvalue than a large-sized two-pole motor having the same output as thewiper motor 110. However, since no thrust bearing is provided on bothend sides of the armature shaft 124 in the axial direction, sliding lossof the armature shaft 124, namely, frictional resistance between thearmature shaft 124 and the thrust bearing is correspondingly removed, sothat increase in excessive calorific value is prevented.

As shown in FIG. 14, the reduction gear mechanism section 130 isprovided with a housing 131 formed into an approximately bathtub shapeby casting molten aluminum material or the like. The housing 131 isprovided with a bottom portion 131 a and a wall portion 131 b, where anopposite side to the bottom portion 131 a is formed as an openingportion 131 c. The opening portion 131 c is closed by a gear cover (notshown) and the worm wheel 132, the connector unit 150, and the like areaccommodated within the housing 131 from the opening portion 131 c.

A bush holder accommodating portion 134 is integrally provided on theside of the motor portion 120 of the housing 131. The bush holderaccommodating portion 134 is formed into a cylindrical shape so as toextend along the axial direction of the armature shaft 124, across-sectional shape thereof is formed into an approximately oval shapelike the cross-sectional shape of the motor case 121 (see FIG. 15).Thereby, thinning of the brush holder accommodating portion 134 is alsoachieved in the brush holder accommodating portion 134 by saving awidthwise size of the brush holder accommodating portion 134, namely, athickness size thereof in a depth direction in FIG. 14.

A worm wheel (a rotating body) 132 shown in FIG. 16 is rotatablyprovided within the housing 131, and the worm wheel 132 is formed intoan approximately disc shape by injection-molding resin material such asplastic. Gear teeth 132 a is integrally provided on an outercircumferential portion of the worm wheel 132, and a worm gear 124 a(see FIG. 14) is caused to mesh with the gear teeth 132 a.

One end side of a wheel shaft 132 b composed of a steel rod circular insection in an axial direction thereof is fixed to a rotation center ofthe worm wheel 132, and the other end side of the wheel shaft 132 b ispivotally supported by a boss portion (not shown) provided on the bottomportion 131 a of the housing 131.

A pair of outer circumferential side engagement holes 132 c facing eachother so as to sandwich the wheel shaft 132 b are provided on the wormwheel 132 nearer to the gear teeth 132 a than the wheel shaft 132 b.Furthermore, a pair of inner circumferential side engagement holes 132 dfacing each other so as to sandwich the wheel shaft 132 b is provided onthe worm wheel 132 nearer to the wheel shaft 132 b than the gear teeth132 a. The respective outer circumferential side engagement holes 132 cand the respective inner circumferential side engagement holes 132 d arearranged at positions rotated relative to each other about the axialcenter of the wheel shaft 132 b by about an angle of 90 degrees.

Respective fixing claws 133 c and 133 d for fixing the switching plate133 to the worm wheel 132 are inserted into respective engagement holes132 c and 132 d to be attached thereto. Thereby, the outercircumferential portion 133 a and the inner circumferential portion 133b of the switching plate 133 can be firmly fixed to the worm wheel 132without causing chattering.

A switching plate (a conductive plate) composed of a steel plate havingconductivity is provided on the side of the bottom portion 131 a of theworm wheel 132, as shown by a slanted line portion in FIG. 16. Theswitching plate 33 is formed of brass excellent in conductivity or thelike, and it is formed in an approximately annular shape by performingpress work (punching or the like).

Outer circumferential side fixing claws (fixing claws) 133 c and innercircumferential side fixing claws (fixing claws) 133 d bent at anapproximately right angle in a plate thickness direction of theswitching plate 133 are provided by twos on the outer circumferentialportion 133 a and the inner circumferential portion 133 b of theswitching plate 133, respectively. The respective fixing claws 133 c andthe respective fixing claws 133 d are provided corresponding to therespective engagement holes 132 c and the respective engagement holes132 d. That is, the respective outer circumferential side fixing claws133 c and the respective inner circumferential side fixing claws 133 dare arranged at positions rotated relative to each other about the axialcenter of the wheel shaft 132 b by about an angle of 90 degrees.

A recessed portion 133 e recessed inwardly in a diametrical direction ofthe switching plate 133 is provided at one portion of the outercircumferential portion 133 a of the switching plate 133. Furthermore, aprojection portion 133 f projecting inwardly in a diametrical directionof the switching plate 133 is provided at one portion of the innercircumferential portion 133 b of the switching plate 133. Furthermore,an annular plate main body 133 g which is not provided with a projectionand a recess is provided between the outer circumferential portion 133 aand the inner circumferential portion 133 b along the diametricaldirection of the switching plate 133.

A first sliding contact portion 133 h, a second sliding contact portion133 i and a third sliding contact portion 133 j (two-dot chain lines inFIG. 16) extending in the circumferential direction of the switchingplate 133 are formed at a portion corresponding to the plate main body133 g of the switching plate 133, a portion corresponding to therecessed portion 133 e, and a portion corresponding to the projectionportion 133 f, respectively. Distal end portions of a first contactplate CP1 and a second contact plate CP2 provided on the contact unit150 come in sliding contact with the first sliding contact portion 133 hand the second sliding contact portion 133 i according to rotation ofthe worm wheel 132, respectively.

Here, in this embodiment, no member comes in sliding contact with thethird sliding contact portion 133 j. That is, this embodiment has astructure which is not provided with a function of performing braking bygenerating counter electromotive force in the motor section 120.However, since the embodiment has the third sliding contact portion 133j corresponding to the projection portion 133 f, when a braking functionbased upon the counter electromotive force is required, such arequirement can be easily satisfied by only replacing the connector unitwith another connector unit capable of exhibiting the function, namely,a contact plate provided with first to third contact plates. Thus, inthe wiper motor 110, common uses of constituent parts can be achievedand cost reduction is realized. Incidentally, as an electrical circuitexhibiting the braking function based upon the counter electromotiveforce, an electrical circuit (not shown) configured such that a closedloop circuit is formed in response to a rotation position of the wormwheel 132 is used.

Thus, by providing the first contact plate CP1 coming in sliding contactwith the first sliding contact portion 133 h to be always connected tothe switching plate 133 and the second contact plate CP2 coming insliding contact with the second sliding contact portion 133 i to bedisconnected from the switching plate 133 by the recessed portion 133 e,conduction states and non-conduction states of the respective contactplates CP1 and CP2 are fed to a vehicle-mounted controller (not shown)via the connector 150. Thereby, the vehicle-mounted controller detectsthat a wiper switch (not shown) has been turned off by a driver and thatthe respective contact plates CP1 and CP2 have been changed tonon-conduction states (the second contact plate CP2 has reached therecessed portion 133 e), thereby stopping supply of driving current tothe motor section 20. Thereby, the wiper blade can be stopped at apredetermined position.

As shown in FIG. 14, an output shaft 135 composed of a steel rodcircular in section is accommodated in a portion (the left side in FIG.14) of the housing 131 separated from the worm wheel 132. The outputshaft 135 is pivotally supported by a boss portion (not shown) providedon a bottom portion 131 a of the housing 131. A base end portion of thewiper blade is fixed to an extension portion (not shown) of the outputshaft 135 extending outside.

A motion converting mechanism 140 for converting a rotation motion ofthe worm wheel 132 to a swinging motion of the output shaft 135 isprovided between the base end side of the output shaft 135 and the wormwheel 132 within the housing 131. The motion converting mechanism 140 isprovided with a swinging link 141, a coupling plate 142 and a slidingcontact plate 143.

The swinging link 141 is formed into a plate shape by punching a steelplate or the like, one end side of the swinging link 141 in anlongitudinal direction thereof is fixed to the base end side of theoutput shaft 135. On the other hand, the other end side of the swinginglink 141 in the longitudinal direction is pivotally coupled to one endside of the coupling plate 142 in the longitudinal direction via a firstcoupling pin P1. The other end side of the coupling plate 142 in thelongitudinal direction is pivotally coupled at a position on the wormwheel 132 deviated from the rotation center of the worm wheel 132 via asecond coupling pin P2. Here, a length size of the swinging link 141 isset to a length size of approximately half (approximately ½) of a lengthsize of the coupling plate 142. Furthermore, the coupling plate 142 isalso formed into a plate shape by punching a steel plate or the like inthe same manner as the swinging link 141.

Thus, by providing the motion converting mechanism between the outputshaft 135 and the worm wheel 132, the output shaft 135 can be swung in apredetermined angular range according to rotation of the worm wheel 132in one direction. Specifically, a rotation force reduced in speed andhaving raised torque is transmitted to the second coupling pin P2 andthe second coupling pin P2 is rotated about the wheel shaft 132 b.Thereby, the other end side of the coupling plate 142 in thelongitudinal direction is also rotated about the wheel shaft 132 b, sothat the one end side of the coupling plate 142 in the longitudinaldirection is swung about the output shaft 135 in a state where it hasbeen restricted by the swinging link 141 via the first coupling pin P1.

The sliding contact plate 143 is formed into a plate shape from resinmaterial such as plastic excellent in self-lubricity, and it is attachedto the gear cover side (on the near side in FIG. 14) of the couplingplate 142. A sliding contact portion 143 a coming in sliding contactwith the gear cover is integrally provided at a central portion of thesliding contact plate 143 in the longitudinal direction, and grease (notshown) is applied to the sliding contact portion 143 a. Thereby, motionof the motion converting mechanism 140 within the housing 131 is madesmooth and the motion converting mechanism 140 is prevented fromchattering along the axial direction (the depth direction in FIG. 14) ofthe output shaft 135.

As shown in FIG. 17, the connector unit 150 is formed into apredetermined shape by injection-molding resin material such as plasticand it is provided with a connector main body 151 formed into a plateshape and a connector connecting portion 152 formed into a box shapehaving a bottom.

The connector unit 150 is provided so as to stride over the armatureshaft 124, and a through cylindrical portion 151 a extending through thearmature shaft 124 (see FIG. 14) is formed at an approximately centralportion of the connector main body 151. An inner diametrical size of thethrough cylindrical portion 151 a is set to a size slightly larger thanan outer diametrical size of the ball bearing 128 (see FIG. 14).Thereby, at an assembling time of the wiper motor 110, the armatureshaft 124 provided with the ball bearing 128 can pass through theconnector main body 151.

A connector connecting portion 152 is arranged on one side of theconnector main body 151 regarding armature shaft 124 (the right side inFIG. 17). On the other hand, a contact plate supporting portion 151 b isintegrally provided on the other side of the connector main body 151regarding the armature shaft 124 (the left side in FIG. 17), and thecontact plate supporting portion 151 b is protruded from a surface 151 cof the connector main body 151 in the axial direction of the armatureshaft 124.

A first contact plate CP1 and a second contact plate CP1 for performingswitching of conduction state to the motor section 120 (see FIGS. 14 and15) are attached on the contact plate supporting portion 151 b inparallel so as to align in the diametrical direction of the armatureshaft 124. The respective contact plates CP1 and CP2 are plugged in fromone side of the connector main body 151 in a short direction (from alower side in FIG. 17) to be fixed to the connector main body 151.

The first contact plate CP1 is always brought into sliding contact withthe switching plate 133 regardless of the rotation position of the wormwheel 132, and it is arranged on the side of the connector unit 150opposite to the side of the connector connecting portion 152. On theother hand, the second contact plate CP2 passes through the recessedportion 133 e of the switching plate 133 according to rotation of theworm wheel 132, and it is arranged on a portion of the connector unit150 close to the connector connecting portion 152.

Thereby, the second jumper wire JP2 corresponding to the second contactplate CP2 is shorter that the first jumper wire JP1 corresponding to thefirst contact plate CP1. Here, the respective jumper wires JP1 and JP2are conductor wires electrically connecting the respective contactplates CP1 and CP2 and base end sides of respective male type terminalsTM1 or base end sides of respective female type terminals TM2 providedon the side of the connector connecting portion 152, and these membersare connected to each other by a spot welding or the like, respectively.

A plurality of male type terminals TM1 and a plurality of female typeterminals TM2 are provided on the side of the connector connectingportion 152. An external connector (not shown) on the side of a vehicleconnected to the connector connecting portion 152 is electricallyconnected to distal end sides of the respective male type terminals TM1,and respective male type terminals (not shown) provided in the brushholder 170 are plugged in distal end sides of the respective female typeterminals TM2 to be connected thereto.

Here, the connector unit 150 is not provided with an electrical circuitexhibiting a braking function based upon the counter electromotive forceas described above, and it is provided with only two of the firstcontact plate CP1 and the second contact plate CP2. Therefore, as shownin FIG. 16, the widthwise size W of the connector unit 150 is shortened,which results in size reduction and weight reduction of the wiper motor110. Incidentally, when a third contact plate (not shown) exhibiting abraking function based upon a counter electromotive force is provided,the widthwise size of the connector unit becomes large because it isnecessary to bring the third contact plate into sliding contact with thethird sliding contact portion 133 j.

Next, such a point that a stop position accuracy of the wiper motor 110formed in the above manner (the braking function based upon the counterelectromotive force is absent) is improved as compared with acomparative example will be described in detail with reference to thedrawings.

As shown in the second Embodiment in FIG. 18(a), when the wiper switchis turned off from a state where the worm wheel 132 is rotating in adirection of arrow R (in a counterclockwise direction) by a driver,supply of driving current to the motor portion 120 (see FIGS. 14 and 15)is continuously performed in such a case that the second contact plateCP2 (see FIG. 16) is in sliding contact with the second sliding contactportion 133 i and it is being electrically connected to the switchingplate 133 (in the case of the conduction state). That is, though thewiper switch has been turned off, the wiper motor 110 (see FIG. 14) iscontinuously driven. Thereby, the wiper blade is moved toward thepredetermined stop position.

Thereafter, when the second contact plate PC2 reaches the recessedportion 133 e, the supply of driving current to the motor section 120 isstopped and the wiper motor 110 is stopped. At this time, the worm wheel132 is rotated by inertia, and the second contact plate CP2 advanceswithin the recessed portion 133 e by a distance L1 to be stopped at astop point SP. Thereby, the wiper blade is stopped at the predeterminedstop position. Here, the distance L1 where the second contact plate CP2has advanced within the recessed portion 133 e by inertia is, forexample, 3.0 mm, and a rotation angle of the worm wheel 132 is β° (about12°) corresponding to the advance.

On the other hand, as shown in [Comparative Example] in FIG. 18(b),since a recessed portion “b” corresponding to a second sliding contactportion “a” is in the inner circumferential portion of a switching plate“c”, if the second contact plate advances within the recessed portion“b” by a distance L1 (for example, 3.0 mm) to be stopped at the stoppoint SP, a rotation angle of a worm wheel “d” becomes an angle γ°(about an angle of 24 degrees) larger than the above β° (about an angleof 12 degrees) (γ°>β°).

This means that when fluctuation occurs in the magnitude of the distanceL1 due to the magnitude of an external force loaded on the wiper blade,the comparative example can be deteriorated in stop position accuracy ascompared with the second embodiment. Furthermore, as shown in FIGS.18(a) and 18(b), the respective recessed portions 133 e and “b” areformed at the same angle range α° of the respective worm wheels 132 and“d”, and a length size L2 of the recessed portion 133 e along thecircumferential direction (the second embodiment) can be set to a lengthsize longer than a length size L3 of the recessed portion “b” in thecircumferential direction (the comparative example) (L2>L3).

Therefore, even if the worm wheel 132 is largely rotated by inertia, thesecond contact plate CP2 is not rotated beyond the recessed portion 133e so that the wiper motor 110 can be securely stopped in the secondembodiment. On the other hand, in the comparative example, since therecan occur a possibility that when the worm wheel “d” is largely rotatedby inertia, the second contact plate moves beyond the recessed portion“b”, the braking function based upon the counter electromotive force isrequired.

As described in detail, according to the wiper motor 110 according tothe second embodiment, since the recessed portion 133 e through whichthe second contact plate CP2 passes according to rotation of the wormwheel 132 is provided at a portion of the outer circumferential portion133 a of the switching plate 133, the rotation angle β° of the wormwheel 132 can be made small relative to the distance L1 (for example,3.0 mm) where the second contact plate CP2 advances within the recessedportion 133 e by inertia, which results in that fluctuation of the stopposition of the worm wheel 132 becomes hard to occur as compared withthe comparative example. Thereby, it becomes possible to not onlyachieve size reduction and weight reduction of the wiper motor 110 butalso improve the stop position accuracy of the worm wheel 132.

Furthermore, according to the wiper motor 110 according to the secondembodiment, since the projection portion 133 f projecting inwardly inthe diametrical direction of the switching plate 133 is provided on oneportion of the inner circumferential portion 133 b of the switchingplate 133, a function of generating a counter electromotive force toperform braking can be added to the motor section 120, which canaccommodate various needs.

Furthermore, according to the wiper motor 110 according to the secondembodiment, since the recessed portion 133 e is formed at one portion ofthe outer circumferential portion 133 a of the switching plate 133,generation of a useless portion of a base material (a material) of theswitching plate can be suppressed as compared with the case where theprojection portion has been formed at one portion of the outercircumferential portion of the switching plate of the comparativeexample (see FIG. 18(b)), so that yield can be improved.

Third Embodiment

Hereinafter, a third embodiment of the present invention will bedescribed in detail with reference to the drawings. Portions of thethird embodiment having functions similar to those of theabove-described second embodiment are attached with same reference signsand detailed explanation thereof is omitted.

FIG. 19 shows a plan view showing a reduction gear mechanism section ofa wiper motor according to the third embodiment.

As shown in FIG. 19, a wiper motor (a motor apparatus) 180 according tothe third embodiment is different in a position of an output shaft 135and a structure of a motion converting mechanism 190 from the wipermotor 110 (see FIG. 14) according to the second embodiment.

The output shaft 135 of the wiper motor 180 is arranged on the oppositeside of the worm wheel 132 from an armature shaft 124. Thereby, a sizeof the wiper motor 180 along the axial direction of a armature shaft 124can be reduced as compared with that of the second embodiment.

The motion converting mechanism 190 of the wiper motor 180 is providedwith a pinion gear 191, a motion converting member 192, a coupling plate142 and a sliding contact plate 143. The pinion gear 191 is fixed to abase end portion of the output shaft 135, and it is swung together withthe output shaft 135.

The motion converting mechanism 192 is provided with a sector gear 192 ameshing with the pinion gear 191 and an arm portion 192 b pivotallycoupled at an eccentric position on the worm wheel 132 via a secondcoupling pin P2. A first coupling pin P1 is provided at a centralportion of the sector gear 192 a, and the coupling plate 142 is providedbetween the first coupling pin P1 and the output shaft 135.Specifically, one end side of the coupling plate 142 in a longitudinaldirection thereof is pivotally coupled to a base end side of the outputshaft 135, and the other end side of the coupling plate 142 in thelongitudinal direction is pivotally coupled to the first coupling pinP1. Thus, the coupling plate 142 according to the third embodiment keepsa distance between the output shaft 135 and the first coupling pin P1constant to maintain meshing of the pinion gear 191 and the sector gear192 a with each other.

In the motion converting mechanism 190 of the wiper motor 180, therotating motion of the worm wheel 132 is also converted to the swingingmotion of the output shaft 135. Specifically, when the second couplingpin P2 is rotated about a wheel shaft 132 b according to rotation of theworm wheel 132, an arm portion 192 b of the motion converting member 192is also rotated about the wheel shaft 132 b. Thereby, the sector gear192 a is swung about the first coupling pin P1, so that the pinion gear191 meshing with the sector gear 192 a, namely the output shaft 135 isswung.

As described above in detail, the wiper motor 180 according to the thirdembodiment also achieves function and advantageous effect similar tothose of the above-described second embodiment.

The present invention is not limited to the above embodiment, and itgoes without saying that the present invention can be variously modifiedwithout departing from the gist thereof. For example, in the aboveembodiment, the motor case 121 and the brush holder accommodatingportion 134 whose cross-sectional shapes have been formed into an ovalshape, respectively have been shown, but the present invention is notlimited to this shape, and the motor case 121 and the brush holderaccommodating portion 134 can be formed into an elliptical shape, arectangular shape, or the like.

Furthermore, in the above-described embodiment, the configurationadopting the reduction gear mechanism (the worm reducer) composed of theworm gear 124 a and the worm wheel 132 has been shown, but the presentinvention is not limited to this reduction gear mechanism, and, forexample, a planetary gear reducer can be adopted as the reduction gearmechanism. In this case, for example, such a configuration can beadopted that a sun gear is used an input side (on the same side as thearmature shaft 124) gear while a ring rear is used as a gear on theoutput side (on the same side as the output shaft 135).

In addition, in the above-described embodiment, such a case has beenshown that a ferrite magnet is adopted as each magnet 122, but thepresent invention is not limited to the case and a plate-like magnetcomposed of neodymium magnet or the like can be adopted. The number ofmagnets, the number of segments, the number of teeth and the like can bearbitrarily set in response to the specification required for the motorsection.

Fourth Embodiment

Hereinafter, a fourth embodiment of the present invention will bedescribed in detail with reference to the attached drawings.

FIG. 20 is a plan view of a wiper motor according to a fourthembodiment, FIG. 21 is a partially-sectional view taken along line A-A IFIG. 20, FIG. 22 is a perspective view of a worm wheel component asviewed from a surface side, FIG. 23 is a perspective view of the wormwheel component as viewed from a back side, FIG. 24 is apartially-enlarged view for explaining a positional relationship of acoupling portion, a recessed portion close to a gear portion, and arecessed portion close to a wheel shaft fixing hole, FIG. 25 is anexplanatory view for explaining a size relationship of a firstcylindrical portion, a second cylindrical portion, and the recessedportion close to the gear portion, and FIG. 26 is a view of a connectorunit and a worm wheel as viewed from a back side in FIG. 20.

As shown in FIG. 20, a wiper apparatus 210 as motor apparatus is used asa drive source of a rear wiper apparatus (not shown) mounted on a rearhatch of a vehicle, and provided with a motor section 220 and areduction gear mechanism section 230. The motor section 220 and thereduction gear mechanism section 230 are integrally coupled to eachother by a pair of fastening screws 211. The wiper motor 210 is arrangedin a narrow space such as a rear hatch, and configured to cause a wiperblade (not shown) provided on a rear glass (not shown) to perform areciprocating wiping action (swinging drive) within a predeterminedangular range.

As shown in FIGS. 20 and 21, the motor section 220 is constituted as afour-pole motor with brush. The motor section 220 is provided with amotor case 221, and the motor case 221 is formed into a bottomedcylindrical shape by performing deep drawing work to a steel plate whichis a magnetic body. The motor case 221 is provided with a pair ofarc-shaped portions 221 a and a pair of straight portions 121 b, and therespective arc-shaped portions 221 a and the respective straightportions 221 b are arranged so as to face each other via a shaft center(an armature shaft 224) of the motor case 221, respectively. Thereby, across-sectional shape of the motor case 221 is formed into anapproximately oval shape. Therefore, thinning can be achieved by savinga widthwise size of the motor case 221, namely, a thickness size in acrosswise direction in FIG. 21.

The respective arc-shaped portions 221 a and the respective straightportions 221 b extend from an opening portion side of the motor case 221to a bottom portion side thereof. Thereby, the motor case 221 is formedinto a straight shape which does not include any stepped portion, whichresults in improvement of ease of the deep drawing work of the motorcase 221. Furthermore, as shown in FIG. 20, since a brush holder 270does not enter the opening portion side of the motor case 221, a lengthof the motor case 221 in an axial direction is also suppressed. Thus,the motor case 221 is formed into an advantageous shape regardingimprovement of moldability, and size reduction and weight reduction.

A total of four magnets 222 formed into an approximately arc shape insection are attached inside the motor case 221. The respective magnets222 are ferrite magnets, for example, and they are fixed along acircumferential direction of the motor case 221 at equal intervals (atintervals of 90 degrees) and an armature 223 is rotatably accommodatedin the respective magnets 222 with a predetermined gap. A base end sideof an armature shaft (rotation shaft) 224 penetrates a rotation centerof the armature 223, and is fixed to it.

A commutator 225 is fixed to an approximately central portion of thearmature shaft 224 along an axial direction thereof, and the commutator225 is provided with ten segments 225 a. Furthermore, an armature core226 forming the armature 223 is fixed on the side of a base end of thearmature shaft 224, and the armature core 226 is provided with ten teeth226 a. Slots are formed among the respective teeth 226 a. A plurality ofarmature coils 226 a is wound on the respective teeth 226 a by apredetermining winding method with a predetermined number of turns. Coilends of the armature coils 226 b are respectively electrically connectedto the segments 225 a.

A plurality of current-feeding brushes 225 b (only one is shown in FIG.20) comes in sliding contact with each segment 225 a of the commutator225. Each power-supply brush 225 b is movably provided on the brushholder 270 accommodated in the brush holder accommodating portion 234 ofthe housing 231. Driving current from the connector unit 250 is suppliedto each power-supply brush 225 b. Thus, the motor section 220 and theconnector unit 250 are electrically connected via each power-supplybrush 225 b, the commutator 225 and the armature coil 226 b, so thatelectromagnetic force is generated in the armature coil 226 b and thearmature 223 (the armature shaft 224) is rotated. Incidentally, in FIG.20, illustration of each power-supply brush 225 b and the brush holder270 is omitted for convenience of explanation.

The base end side of the armature shaft 224 is rotatably accommodated inthe motor case 221, and it is supported by only a radial bearing 227provided on the bottom portion side of the motor case 221. A thrustbearing supporting the armature shaft 224 from its axial direction isnot provided between the base end side of the armature shaft 224 and themotor case 221. Here, the radial bearing 227 is formed into anapproximately cylindrical shape from, for example, a sintered material,so that the radial bearing 227 is provided with low noise, impactresistance, and self-lubrication and it is hard to generate frictionpowder. However, the radial bearing 227 may also be formed of a plasticmaterial excellent in heat resistance or the like instead of thesintered material.

A worm gear 224 a (not shown in detail) is integrally provided at adistal end side of the armature shaft 224, and the worm gear 224 a isrotated within the housing 231 according to rotation of the armatureshaft 224. The worm gear 224 a is formed into a spiral shape, and it iscaused to mesh with gear teeth 280 a of the worm wheel 280. Here, theworm gear 224 a and the worm wheel 280 constitute a reduction gearmechanism. The worm wheel 280 is rotated in a state speed-reduced fromrotation speed of the worm gear 224 a according to rotation of the wormgear 224 a to reduce rotation speed and output rotation with elevatedtorque to the output.

An inner wheel member 228 a of a ball bearing 228 is fixed between thearmature 223 and the worm gear 224 a of the armature shaft 224 bypress-fitting. Furthermore, an outer wheel member 228 b of the ballbearing 228 is held between the housing 231 and a stopper plate 260.Thereby, the armature shaft 224 is rotatably supported by the ballbearing 228 and it is restricted regarding movements in an axialdirection and in a radial direction thereof to the housing 231. Thus,the ball bearing 228 is provided with functions serving as a radialbearing and as a thrust bearing. Therefore, a thrust bearing supportingthe armature shaft 224 from the axial direction of the armature shaft224 is not also provided between the distal end side of the armatureshaft 224 and the housing 231.

Here, since the wiper motor 210 is constituted as a four-pole motorsize-reduced and weight-reduced, for example, it is more in calorificvalue than a large-sized two-pole motor having the same output as thewiper motor 210. However, since no thrust bearing is provided on bothend sides of the armature shaft 224 in the axial direction, sliding lossof the armature shaft 224, namely, frictional resistance between thearmature shaft 224 and the thrust bearing is correspondingly removed, sothat increase in excessive calorific value is prevented.

As shown in FIG. 20, the reduction gear mechanism section 230 isprovided with a housing 231 formed into an approximately bathtub shapeby casting molten aluminum material or the like. The housing 231 isprovided with a bottom portion 231 a and a wall portion 231 b, where anopposite side to the bottom portion 231 a is formed as an openingportion 231 c. The opening portion 231 c is closed by a gear cover (notshown) and the worm wheel 280, the connector unit 250, and the like areaccommodated within the housing 231 from the opening portion 231 c.

A bush holder accommodating portion 234 is integrally provided on thesame side of the housing 231 as the motor portion 220. The bush holderaccommodating portion 234 is formed into a cylindrical shape so as toextend along the axial direction of the armature shaft 224, across-sectional shape thereof is formed into an approximately oval shapelike the cross-sectional shape of the motor case 221 (see FIG. 21).Thereby, thinning of the brush holder accommodating portion 234 is alsoachieved in the brush holder accommodating portion 234 by saving awidthwise size of the brush holder accommodating portion 234, namely, athickness size thereof in a depth direction in FIG. 20.

The worm wheel 280 as a rotating body shown in FIGS. 22 and 23 isrotatably provided within the housing 231, and the worm wheel 280 isformed into an approximately disc shape by injection-molding resinmaterial such as plastic. The worm wheel 280 are provided with a mainbody portion 281 and a gear wheel portion 282 larger in diameter andsmaller in axial thickness than the main body portion 281. Gear teeth280 a is integrally provided on an outer circumferential portion of gearwheel portion 282, and a worm gear 224 a (see FIG. 20) is caused to meshwith the gear teeth 280 a.

A wheel shaft fixing hole 281 a is provided at a rotation center of themain body portion 281, and one end side of a wheel shaft 280 b (see FIG.20) composed of a steel rod circular in section in the axial directionis fixed to the wheel shaft fixing hole 281 a. Here, the other end sideof the wheel shaft 280 b in the axial direction is pivotally supportedat a boss portion (not shown) provided on a bottom portion 231 a of thehousing 231.

Furthermore, peripheries of one side and the other side of the wheelshaft fixing hole 281 a in the axial direction thereof are formed with aplurality of first recessed portions 281 b recessed in the axialdirection of the main body portion 281. Each first recessed portion 281b functions as the so-called “thickness reduction” and it suppressesoccurrence of shrinkage, warp or the like about the wheel shaft fixinghole 281 a in the main body portion 281, thereby improving a moldingprecision of the wheel shaft fixing hole 281 a. Thereby, the worm wheel280 can be rotated smoothly without being strained, so that reduction ofoperating noises of the wiper motor 210 or the like can be achieved.

As shown in FIG. 22, a pair of coupling portions 281 c provided withplug-in holes 281 c 1 are provided on one side of the main body portion281 in the axial direction. The coupling pin 283 (see FIGS. 20 and 25)coupled with on side (the right side in FIG. 20) of the motionconverting mechanism 240 driven according to rotation of the worm wheel280 is plugged in either one of the respective plug-in holes 281 c 1.That is, the coupling pin 283 is attached to either one of therespective coupling portions 281 c. The respective coupling portions 281c are arranged at positions spaced away from the wheel shaft fixing hole281 a which is the rotation center of the worm wheel 280 so as to beopposed to each other through the wheel shaft fixing hole 281 a. Therespective coupling portions 281 c are provided nearer to a gear wheelportion 282 on the diametrical-direction outside of the main bodyportion 281.

Here, the attaching position of the coupling pin 283 can be changed toone or the other of the respective coupling portions 281 c, but this isbecause various specifications of the wiper motor 210 can beaccommodated. Specifically, for example, when the coupling pin 283 isattached to either one of the respective coupling portions 281 c, thestop position of the wiper blade faces right, and when the coupling pin283 is attached to the other of the respective coupling portions 281 c,the stop position of the wiper blade faces left. In other words, theworm wheel 280 is formed into a shape allowing common use of a part,which contributes to manufacturing cost reduction of the wiper motor210.

As shown in FIG. 25, the coupling portion 281 c is provided with a firstcylindrical portion 281 d arranged inwardly in a diametrical dictionthereof and a second cylindrical portion 281 e arranged outwardly in thediametrical direction. Here, for clarifying the positional relationshipbetween the first cylindrical portion 281 d and the second cylindricalportion 281 e, a two-dot chain line is applied to a boundary betweenthese portions 281 d and 281 e.

The first cylindrical portion 281 d is configured to pivotally supportthe coupling pin 283, and an axial-direction size thereof is set to U.On the other hand, the second cylindrical portion 281 e is providedaround the first cylindrical portion 281 d to partially reinforce thefirst cylindrical portion 281 d, and a axial-direction size thereof isset to an axial-direction size L2 shorter than that of the firstcylindrical portion 281 d (L2<L1). Here, the second cylindrical portion281 e particularly partially reinforces a supporting portion “P”supporting the coupling pin 283 of the first cylindrical portion 281 d,thereby, making rigidity of the portion supporting the coupling pin 283of the coupling portion 281 c sufficient.

Furthermore, by setting the axial-direction size L1 of the firstcylindrical portion 281 d to be longer than the axial-direction size L2of the second cylindrical portion 281 e, a step-like step differenceportion 281 f is formed on one side (the upper side in FIG. 25) of thesecond cylindrical portion 281 e in the axial direction. That is, athickness size along the diametrical direction (corresponding to athickness size of the first cylindrical portion 281 d) is made thin in aportion corresponding to the step difference portion 281 f of thecoupling portion 281 c, so that occurrence of shrinkage, warp, or thelike at a molding time of the coupling portion 281 c can be suppressed.

As shown in FIG. 22, a large-diameter hole portion 281 g serving as thesecond recessed portion and a small-diameter hole portion 281 h smallerin diameter than the large-diameter hole portion 281 g are provided oneby one on one side (an upper side in FIG. 22) of the main body portion281 regarding a line segment LN formed by connecting the centers C ofthe respective coupling portions 281 c. Furthermore, a large-diameterhole portion 281 g serving as the second recessed portion and asmall-diameter hole portion 281 h are provided one by one on the otherside (a lower side in FIG. 22) of the main body portion 281 regardingthe line segment LN. A pair of large-diameter hole portions 281 g arearranged so to be opposed to each other through the wheel shaft fixinghole 281 a, while a pair of small-diameter hole portions 281 h arearranged so as to be opposed to each other through the wheel shaftfixing hole 281 a.

Thus, by providing the same number of large-diameter hole portions 281 gand the same number of small-diameter hole portions 281 h which arerecessed in the axial direction of the main body portion 281 (one byone) on the one side of the main body portion 281 regarding the linesegment LN and the other side of the main body portion 281 regarding theling segment LN, and causing the large-diameter hole portions 281 g andthe small-diameter hole portions 281 h to be opposed to each otherthrough the wheel shaft fixing hole 281 a, balance of the worm wheel 280about the wheel shaft fixing hole 281 a is made excellent. Thereby,rotation wobbling of the worm wheel 280 is suppressed.

Furthermore, since the respective large-diameter hole portions 281 g andthe small-diameter hole portions 281 h reduce the weight of the wormwheel, but function as “thickness reduction”, shrinkage, warp or thelike is prevented from occurring in the worm wheel 280, so that amolding precision of the worm wheel 280 is improved. However, theembodiment is not limited to the case where the large-diameter holeportions 281 g and the small-diameter hole portions 281 h are providedone by one on one side and the other side of the main body portion 281regarding the line segment LN, respectively, and they may be providedtwo by two. Furthermore, only the large-diameter hole portions 281 g maybe provided, and only the small-diameter hole portions 281 h may beprovided.

Furthermore, a plurality of second recessed portions 281 i recessed inthe axial direction of the main body portion 281 is provided on the oneside of the main body portion 281 regarding the line segment LN and theother side of the main body portion 281 regarding the line segment LN inaddition to the respective holes 281 g, 281 h. The respective secondrecessed portions 281 i also serve as “thickness reduction”, and theyprevent occurrence of shrinkage, warp, or the like in the worm wheel280.

Here, inner diametrical sizes of the respective large-diameter holeportions 281 g and inner diametrical sizes (diameter sizes of theplug-in holes 281 c 1) of the respective first cylindrical portions 281d are set to the same size, respectively, so that the coupling pin 283can also be pivotally plugged in the respective large-diameter holeportions 281 g. That is, the respective large-diameter hole portions 281g are also provided with functions for accommodating variousspecifications of the wiper motor 210. Specifically, the respectivelarge-diameter hole portions 281 g are arranged internally in thediametrical direction rather than the respective first cylindricalportions 281 d. Therefore, in the case where the respectivelarge-diameter hole portions 281 g are selected, the wiping range (theswinging range) of the wiper blade can be set to be an angle narrowerthan that in the case where the respective first cylindrical portions281 d are selected.

As shown in FIG. 23, gear wheel-side recessed portions 281 j and wheelshaft-side recessed portions 281 k are provided as the first recessedportion on the other side of the main body portion 281 in theaxial-direction at portions corresponding to the respective couplingportions 281 c (see FIG. 22), respectively. As shown in FIG. 24, therespective gear wheel-side recessed portions 281 j and the respectivewheel shaft-side recessed portions 281 k are formed into anapproximately arc shape in cross-sectional shape, and they are arrangedalong the circumferential directions of the respective coupling portions281 c.

Here, the respective gear wheel-side recessed portions 281 j and therespective wheel shaft-side recessed portions 281 k are recessed towardone side of the main body portion 281 in the axial direction, therebyreducing the volumes of the respective coupling portions 281 c. Depthsizes, namely, sizes in the axial direction, of the respective gearwheel-side recessed portions 281 j and the respective wheel shaft-siderecessed portions 281 k are set to a depth size D slightly reaching thesupporting portion “P” so as to be capable of suppressing occurrence ofshrinkage, warp, the like at a molding time of the coupling portions 281c without lowering the rigidity of a portion of the coupling portions281 c supporting the coupling pin 283.

Furthermore, as shown in FIG. 23, an annular recessed portion 281 mattached with a switching plate 284 (see FIG. 26) is formed on the otherside of the main body portion 281 in the axial direction. A depth size(a size in the axial direction) of the annular recessed portion 281 m isset to the same size as a thickness size (not shown) of the switchingplate 284 composed of a steel plate having conductivity. Therefore, aface of the other side of the main body portion 281 in the axialdirection becomes flush in the state where the switching plate 284 hasbeen attached to the annular recessed portion 281 m.

A pair of outer circumferential side engagement holes 281 n facing eachother so as to sandwich the wheel shaft fixing hole 281 a are providednearer to the gear teeth 280 a of the main body portion 281.Furthermore, a pair of inner circumferential side engagement holes 281 pfacing each other so as to sandwich the wheel shaft fixing hole 281 a isprovided nearer to the gear teeth 280 a of the main body portion 281.The respective outer circumferential side engagement holes 281 n and therespective inner circumferential side engagement holes 281 p arearranged at positions rotated relative to each other about the axialcenter of the wheel shaft fixing hole 281 a by about an angle of 90degrees.

Respective fixing claws 284 c and 284 d (see FIG. 26) for fixing theswitching plate 284 to the annular recessed portion 281 m are insertedand fixed to the respective engagement holes 281 n and 281 p. Thereby,the outer circumferential portion 284 a and the inner circumferentialportion 284 b (see FIG. 26) of the switching plate 284 can be firmlyfixed to the worm wheel 280 without causing chattering.

A switching plate 284 which is a conductive plate is provided on theother side of the worm wheel 280 in its axial direction (on the nearside in this figure), as shown by a slanted line portion in FIG. 26. Theswitching plate 284 is formed of brass excellent in conductivity or thelike, and it is formed into an approximately annular shape by performingpress work (punching or the like). Furthermore, the switching plate 284is fixed to the annular recessed portion 281 m on the other side of theworm wheel 280 in its axial direction.

Two outer circumferential side fixing claws 284 c and two innercircumferential side fixing claws 284 d bent at an approximately rightangle in a plate thickness direction of the switching plate 284 areprovided on the outer circumferential portion 280 a and the innercircumferential portion 280 b of the switching plate 284, respectively.The fixing claws 284 c and 284 d for fixing the switching plate 284 tothe worm wheel 280 are respectively provided to the correspondingengagement holes 281 n and 281 p. That is, the respective outercircumferential side fixing claws 284 c and the respective innercircumferential side fixing claws 284 d are arranged at positionsrotated relative to each other about the axial center of the wheel shaftfixing hole 281 a by about an angle of 90 degrees.

A recessed portion 284 e recessed inwardly in a diametrical direction ofthe switching plate 284 is provided at one portion of the outercircumferential portion 284 a of the switching plate 284. Furthermore, aprojection portion 284 f projecting inwardly in a diametrical directionof the switching plate 284 is provided at one portion of the innercircumferential portion 284 b of the switching plate 284. Furthermore,an annular plate main body 284 g which is not provided with a projectionand a recess is provided between the outer circumferential portion 284 aand the inner circumferential portion 284 b along the diametricaldirection of the switching plate 284.

A first sliding contact portion 284 h, a second sliding contact portion284 i and a third sliding contact portion 284 j (two-dot chain lines inthis figure) extending in the circumferential direction of the switchingplate 284 are respectively formed at a portion corresponding to theplate main body 284 g of the switching plate 284, a portioncorresponding to the recessed portion 284 e, and a portion correspondingto the projection portion 284 f. Distal end portions of a first contactplate CP21 and a second contact plate CP22 provided on the contact unit250 come in sliding contact with the first sliding contact portion 284 hand the second sliding contact portion 284 i according to rotation ofthe worm wheel 280, respectively.

Thereby, conduction states and non-conduction states of the respectivecontact plates CP21 and CP22 are fed to a vehicle-mounted controller(not shown) through the connection unit 250. Thereby, thevehicle-mounted controller stops supply of diving current to the motorsection 220 by detecting that a wiper switch (not shown) has been turnedoff by a driver and that the respective contact plates CP21 and CP22have been changed to a non-conductive state, namely, that the secondcontact plate CP22 has reached the recessed portion 284 e. Thereby, thewiper blade can be automatically stopped at the predetermined stopposition (auto stop).

Here, a connector connecting portion 251 is integrally provided in theconnector unit 250, and an external connector (not shown) on the vehicleside is electrically connected to the connector connecting portion 251.Thereby, conduction states and non-conduction states of the respectivecontact plates CP21 and CP22 can be fed to the vehicle-mountedcontroller, and driving current can be supplied from the vehicle-mountedcontroller to a brush holder 270 (the motor section 220).

As shown in FIG. 20, an output shaft 235 composed of a steel rodcircular in section is accommodated in a portion (on the left side inthis figure) of the housing 231 separated from the worm wheel 280. Theoutput shaft 235 is pivotally supported by a boss portion (not shown)provided on a bottom portion 231 a of the housing 231. A base endportion of the wiper blade is fixed to an extension portion (not shown)of the output shaft 235 extending outside.

A motion converting mechanism (power transmission member) 240 forconverting a rotation motion of the worm wheel 280 to a swinging motionof the output shaft 235 is provided between the base end side of theoutput shaft 235 and the worm wheel 280 within the housing 231. Themotion converting mechanism 240 is provided with a swinging link 241, acoupling plate 242 and a sliding contact plate 243.

The swinging link 241 is formed into a plate shape by punching a steelplate or the like, one end side of the swinging link 241 in anlongitudinal direction thereof is fixed to the base end side of theoutput shaft 235. On the other hand, the other end side of the swinginglink 241 in the longitudinal direction is pivotally coupled to one endside of the coupling plate 242 in the longitudinal direction via a pinmember 244. The other end side of the coupling plate 242 in thelongitudinal direction is pivotally coupled to one coupling portion 281c (see FIG. 22) at a position deviated from the rotation center of theworm wheel 280 via a coupling pin 283.

That is, one side (the right side of this figure) of the powerconverting mechanism 240 is coupled to the coupling pin 283, and theother side (the left side of this figure) of the power convertingmechanism 240 is coupled to the output shaft 235. Here, a length size ofthe swinging link 241 is set to a length size of approximately half(approximately ½) of a length size of the coupling plate 242.Furthermore, the coupling plate 242 is also formed into a plate shape bypunching a steel plate or the like in the same manner as the swinginglink 241.

Thus, by providing the motion converting mechanism 240 between theoutput shaft 235 and the worm wheel 280, the output shaft 235 can beswung in a predetermined angular range according to rotation of the wormwheel 280 in one direction. Specifically, a rotation force reduced inspeed by the rotation of the worm gear 224 a and the worm wheel 280 andhaving raised torque is transmitted to the coupling pin 283, and thecoupling pin 283 is rotated about the wheel shaft 280 b. Thereby, theother end side of the coupling plate 242 in the longitudinal directionis also rotated about the wheel shaft 280 b, so that the one end side ofthe coupling plate 242 in the longitudinal direction is swung about theoutput shaft 235 in a state where it has been restricted by the swinginglink 241 via the pin member 244.

The sliding contact plate 243 is formed into a plate shape from resinmaterial such as plastic excellent in self-lubricity, and it is attachedto the gear cover side (on the near side in FIG. 20) of the couplingplate 242. A sliding contact portion 243 a coming in sliding contactwith the gear cover is integrally provided at a central portion of thesliding contact plate 243 in the longitudinal direction, and grease (notshown) is applied to the sliding contact portion 243 a. Thereby, motionof the motion converting mechanism 240 within the housing 231 is madesmooth, the motion converting mechanism 240 is prevented from chatteringalong the axial direction (the depth direction in FIG. 20) of the outputshaft 235, and it is possible to achieve a reduction of operating noisesof the wiper motor 210. In addition, the sliding contact plate 243 isnot shown in FIG. 25.

As described above in detail, according to the wiper motor 210 accordingto the fourth embodiment, since the coupling portion 281 c is formed ofthe first cylindrical portion 281 d pivotally supporting the couplingpin 283 and the second cylindrical portion 281 e provided about thefirst cylindrical portion 281 d and set to the axial-direction size L2shorter than that of the first cylindrical portion 281 d, the firstcylindrical portion 281 d can be reinforced by the second cylindricalportion 281 e. In this case, since the axial-direction sizes of thefirst cylindrical portion 281 d and the second cylindrical portion 281 eare made different from each other, a diameter-direction thickness sizeof the first cylindrical portion 281 d can be partially suppressed byforming the first cylindrical portion 281 d and the second cylindricalportion 281 e in a stepped fashion. Thereby, by reducing the volume ofthe coupling portion 281 c while securing the rigidity thereof,deformation of resin such as shrinkage or warp can be suppressed, whichresults in achievement of reduction of operating noises of the wipermotor 210 and a long life thereof.

Fifth Embodiment

Hereinafter, a fifth embodiment of the present invention will bedescribed in detail with reference to the drawings. Portions of thefifth embodiment having functions similar to those of theabove-described fourth embodiment are attached with same reference signsand detailed explanation thereof is omitted.

FIG. 27 shows a plan view showing a reduction gear mechanism section ofa wiper motor according to the fifth embodiment.

As shown in FIG. 27, a wiper motor (a motor apparatus) 290 according tothe fifth embodiment is different in a position of an output shaft 235and a structure of a motion converting mechanism (power transmissionmember) 200 from the wiper motor 210 (see FIG. 20) according to thefourth embodiment.

The output shaft 235 of the wiper motor 290 is arranged on the oppositeside of the worm wheel 280 from an armature shaft 224, whereby the wipermotor 290 can be reduced in length along the axial direction of thearmature shaft 224 as compared with that of the fourth embodiment.

The motion converting mechanism 200 of the wiper motor 290 is providedwith a pinion gear 201, a motion converting member 202, a coupling plate242 and a sliding contact plate 243. The pinion gear 201 is fixed to abase end side of the output shaft 235, and it is swung together with theoutput shaft 235.

The motion converting mechanism 202 is provided with a sector gear 202 ameshing with the pinion gear 201 and an arm portion 202 b pivotallycoupled at an eccentric position of the worm wheel 280 via a couplingpin 283. A pin member 244 is provided at a central portion of the sectorgear 202 a, and the coupling plate 242 is provided between the pinmember 244 and the output shaft 235. Specifically, one end side of thecoupling plate 242 in a longitudinal direction thereof is pivotallycoupled to a base end side of the output shaft 235, and the other endside of the coupling plate 242 in the longitudinal direction ispivotally coupled to the pin member 244. Thus, the coupling plate 242according to the fifth embodiment keeps a distance between the outputshaft 235 and the pin member 244 constant to maintain meshing of thepinion gear 201 and the sector gear 202 a with each other.

In the motion converting mechanism 200 of the wiper motor 290, therotating motion of the worm wheel 280 is also converted to the swingingmotion of the output shaft 235. Specifically, when the coupling pin 283is rotated about a wheel shaft 282 b according to rotation of the wormwheel 280, the arm portion 202 b of the motion converting member 202 isalso rotated about the wheel shaft 282 b. Thereby, the sector gear 202 ais swung about the pin member 244, so that the pinion gear 201 meshingwith the sector gear 202 a, namely the output shaft 235 is swung.

As described above in detail, the wiper motor 290 according to the fifthembodiment also achieves function and advantageous effect similar tothose of the above-described fourth embodiment.

The present invention is not limited to the above embodiment, and itgoes without saying that the present invention can be variously modifiedwithout departing from the gist thereof. For example, in the aboveembodiment, the motor case 221 and the brush holder accommodatingportion 234, each of which is formed into an oval shape in cross sectionas shown, but the present invention is not limited to this shape, andthe motor case 221 and the brush holder accommodating portion 234 can beformed into an elliptical shape, a rectangular shape, or the like.

Furthermore, in the above-described embodiment, the configurationadopting the reduction gear mechanism (the worm reducer) composed of theworm gear 224 a and the worm wheel 280 has been shown, but the presentinvention is not limited to this reduction gear mechanism, and, forexample, a planetary gear reducer can be adopted as the reduction gearmechanism. In this case, for example, such a configuration can beadopted that a sun gear is used an input side (on the same side as thearmature shaft 224) gear while a ring rear is used as a gear on theoutput side (on the same side as the output shaft 235).

In addition, in the above-described embodiment, such a case has beenshown that a ferrite magnet is adopted as each magnet 222, but thepresent invention is not limited to the case and a plate-like magnetcomposed of neodymium magnet or the like can be adopted. The number ofmagnets, the number of segments, the number of teeth and the like can bearbitrarily set in response to the specification required for the motorsection.

Sixth Embodiment

Hereinafter, a sixth embodiment of the present invention will bedescribed in detail with reference to the drawings.

FIG. 28 is a plan view of an electric motor apparatus 301 according to asixth embodiment. FIG. 28 shows it with a housing cover off which willbe described below.

The electric motor apparatus (motor apparatus) 301 is used, for example,as an electric motor apparatus for rear wiper driving (a wiper motor)pivoting a wiper arm such as a rear wiper (not shown). The electricmotor 301 is provided on a back door of a vehicle. A rear wiper (a wiperarm (not shown)) wiping a rear window glass of the vehicle is attachedto an output shaft 360 of the electric motor apparatus 301.

The electric motor apparatus 301 is provided with an electric motorsection (a motor section) 310, a housing 320, a transmission mechanism350, an output shaft 360, and the like.

The electric motor section 310 is a drive source swinging the rearwiper. The housing 320 accommodates the transmission mechanism 350 andsupports the electric motor section 310 and the output shaft 360. Thetransmission mechanism 350 is connected to the electric motor section310 to transmit a rotation force of the electric motor section 310. Theoutput shaft 360 is coupled to the transmission mechanism 350 totransmit the rotation force of the electric motor section 310 to therear wiper.

(Electric Motor Section)

The electric motor section 310 is a so-called “motor with brush”supplying power using a brush.

The electric motor section 310 is provided with a bottomed cylindricalmotor housing 311, an armature (not shown) rotatably arranged within themotor housing 311, and the like.

The motor housing 311 is a member made of metal such as iron, and it isformed by press work for performing deep drawing or the like. Aplurality of magnets is attached to an inner circumferential face of themotor housing 311 by adhesive or the like.

A flange 312 is formed on an opening end of the motor housing 311. Themotor housing 311 is fixed to the housing 320 by bolts inserted intoattaching holes (not shown) of the flange 312.

The armature has a motor shaft 313 and the like. The motor shaft 313 isa rod-shaped member made of metal such as iron. One end (not shown) ofthe motor shaft 313 is supported at a bottom portion of the motorhousing 311. A distal end of the motor shaft 313 is rotatably supportedby the housing 320 through a sliding bearing (a third bearing) 322.

(Housing)

The housing 320 is a member made of, for example, aluminum or the like.The housing 320 is formed by aluminum die-casting. The housing 320 has amotor attaching portion 321, a transmission mechanism accommodatingportion 323, and a sleeve 330, which are formed integrally.

The electric motor section 310 is attached to the motor attachingportion 321. The motor attaching portion 321 and the transmissionmechanism accommodating portion 323 communicate with each other througha through-hole (not shown). A motor shaft 313 (a worm shaft 352) isinserted into the through-hole.

A connector member (a connector unit) 370 for supplying power to theelectric motor section 310 is assembled to the motor attaching portion321. A harness (an external connector, not shown) extending from a powersource (not shown) such as a battery is connected to the connectorhousing 370. Thereby, power is supplied to the electric motor section310.

A sliding bearing 322 is formed on the motor attaching portion 321. Thesliding bearing 322 is formed by cutting work. The sliding bearing 322is arranged coaxially with the through-hole causing the motor attachingportion 321 and the transmission mechanism accommodating portion 323 tocommunicate with each other.

The transmission mechanism accommodating portion 323 is a bottomedbox-shaped region whose one face is opened and it accommodates thetransmission mechanism 350. The transmission mechanism 350 is arrangedon a bottom face 323 s of the transmission mechanism accommodatingportion 323. A plate-shaped housing cover (not shown) is attached to anopening of the transmission mechanism accommodating portion 323 to closean internal space of the transmission mechanism accommodating portion323.

The sleeve 330 is a cylindrical region provided on an outer face of thetransmission mechanism accommodating portion 323 in a standing fashion.The sleeve 330 rotatably supports a base end portion 362 of the outputshaft 360.

(Transmission Mechanism)

The transmission mechanism 350 is composed of a worm shaft 352 formed ata distal end of the motor shaft 313, a worm wheel 354 meshing with theworm shaft 352, a first coupling plate 356 connected to the worm wheel354, and a second coupling plate 358 connected to the first couplingplate 356.

The worm shaft 352 is a shaft-shaped screw gear wheel formed at thedistal end of the motor shaft 313. The worm shaft 352 is formedintegrally with the motor shaft 313.

A base end of the worm shaft 352 is rotatably supported to the housing320 via a sliding bearing 322 attached to the housing 320.

The worm shaft (shaft portion) 352 is supported to the housing 320 in acantilever fashion. A distal end 352 t of the worm shaft 352 is a freeend, and it is not in contact with the housing 320.

The worm wheel 354 is a helical gear, and it is rotatably supported by acenter shaft (not shown) provided on a bottom face 323 s of thetransmission mechanism accommodating portion 323 in a standing manner.The worm wheel 354 meshes with the worm shaft 352 so that a rotationforce of the electric motor section 310 is transmitted from the wormshaft 352 to the worm wheel 354.

A rotation speed of the motor shaft 313 of the electric motor section310 is reduced by the worm shaft 352 and the worm wheel 354. A largespeed reduction ratio can be obtained by the worm shaft 352 and the wormwheel 354. Furthermore, this gear mechanism is smaller in backlash thanthe other gear mechanisms. The worm wheel 354 is rotated according torotation of the worm shaft 352, but the inverse rotation is impossible.

The first coupling plate 356 is a member formed into an elongated flatplate shape. One end side of the first coupling plate 356 is pivotallyconnected to (supported by) a coupling shaft 355 provided on a side face(an upper face) of the worm wheel 354.

The other end side of the first coupling plate 356 is pivotallyconnected to (supported by) one end side of a second coupling plate 358.

The second coupling plate 358 is a member formed into a flat plate shapeshorter than the first coupling plate 356. One end side of the secondcoupling plate 358 is pivotally connected to (supported by) the otherend side of the first coupling plate 356. The other end side of thesecond coupling plate 358 is connected to the output shaft 360. Thesecond coupling plate 358 and the output shaft 360 are connected to eachother so as not to be capable to rotate relative to each other.

The output shaft 360 is rotatably supported to the housing 320 (thesleeve 330) via a sliding bearing (a first bearing) 332 described later,so that the other end side of the second coupling plate 358 is alsorotatably supported to the housing 320.

The worm wheel 354 (the coupling shaft 355), the first coupling plate356 and the second coupling plate 358 constitute a four-node linkmechanism also including the housing 320 (the transmission mechanismaccommodating portion 323).

The coupling shaft 355 is rotationally moved along a circumferentialdirection of the worm wheel 354 according to rotation of the worm wheel354. The first coupling plate 356 coupled to the coupling shaft 355swings the second coupling plate 358 according to the rotationalmovement of the coupling shaft 355. Thereby, the output shaft 360 fixedto the second coupling plate 358 is pivoted (pivoted in a reciprocatingmanner).

(Output Shaft)

The output shaft 360 is a rod-shaped member formed of metal such as, forexample, iron. The output shaft 360 is provided toward the outside ofthe housing 320 (the transmission mechanism accommodating portion 323)in a projecting manner.

An entire length of the output shaft 360 varies corresponding to vehicletypes because it is properly set according to a vehicle type on whichthe electric motor apparatus 301 is mounted.

A base end portion 362 of the output shaft 360 is rotatably supported bythe sleeve 330 of the housing 320. A center hole 331 extending along alongitudinal direction is formed in the sleeve 330. The center hole 331communicates with the transmission mechanism accommodating portion 323of the housing 320.

A base end of the output shaft 360 is coupled to the transmissionmechanism 350. The base end of the output shaft 360 is connected to thesecond coupling plate 358. The output shaft 360 and the second couplingplate 358 are fitted to each other, for example, through a serration anda relative rotation therebetween is restricted.

A screw portion (not shown) is formed at a distal end of the outputshaft 360. A rear wiper is fixed to this screw portion by a nut or thelike.

The output shaft 360 is pivoted in a reciprocating fashion in responseto swinging of the second coupling plate 358. The output shaft 360 ispivoted by one reciprocation for each rotation of the worm wheel 354.The rear wiper attached to the output shaft 360 is swung according tothe reciprocating pivot of the output shaft 360.

(Sleeve and Resin-Made Bush)

FIG. 29 is a view showing the sleeve 330. FIG. 29(a) is sectional viewand FIG. 29(b) is a rear view.

FIG. 30 is a perspective view of a resin-made bush 340.

FIG. 31 is a view showing a whirl-stop mechanism of the resin-made bush340. FIG. 31(a) shows a recessed portion 334 of an accommodating portion333, and FIG. 31(b) shows a projection portion 343 of the resin-madebush 340.

The sleeve 330 rotatably supports the base end portion 362 of the outputshaft 360. The base end portion 362 of the output shaft 360 isaccommodated in the center hole 331 of the sleeve 330.

The sliding bearing 332 supporting the base end portion 362 of theoutput shaft 360 in a sliding contact manner is formed a region of thecenter hole 331 positioned on the distal end side of the sleeve 330.That is, a portion of an inner circumferential face of the center hole331 comes in direct contact with an outer circumferential face of theoutput shaft 360 to rotatably support the output shaft 360. The slidingbearing 332 is formed by cutting the center hole 331.

An accommodating portion 333 larger in diameter than the diameter of theoutput shaft 360 is formed in a region of the center hole 331 positionedon the base end side of the sleeve 330. The accommodating portion 333 isformed so as to be opened to a back face of the sleeve 330 (the bottomface 323 s of the transmission mechanism accommodating portion 323).

The resin-made bush 340 is accommodated in the accommodating portion333. By pushing the resin-made bush 340 from the back face of the sleeve330 (the bottom face 323 s of the transmission mechanism accommodatingportion 323) toward the accommodating portion 333, the resin-made bush340 is accommodated in (attached to) the accommodating portion 333.

The resin-made bush (the second bearing) 340 is an approximatelycylindrical member made of synthetic resin. The resin-made bush 340 isformed of, for example, POM (polyacetal) or the like. Besides POM, theresin-made bush 340 can be formed of PA (polyamide), PTFE(polytetrafluoroethylene) or the like.

The resin-made bush 340 supports the base end portion 362 of the outputshaft 360 in a sliding contact manner like the sliding bearing 332. Aninner circumferential face of the center hole 341 of the resin-made bush340 comes in direct contact with an outer circumferential face of theoutput shaft 360 to rotatably support the output shaft 360.

Thus, the base end portion 362 of the output shaft 360 is supported bythe sliding bearing 332 and the resin-made bush 340. The sliding bearing332 and the resin-made bush 340 receive an external force applied to theoutput shaft 360 to support the output shaft 360 such that the outputshaft 360 does not tilt.

The most base end side of the base end portion 362 of the output shaft360 is supported by the resin-made bush 340. The resin-made bush 340 issmaller in mechanical strength than the sliding bearing 332. That is,the resin-made bush 340 has such a fragility that it is defeated by anexternal force applied to the output shaft 360 be deformed.

Therefore, when a force crossing in the axial direction acts on thedistal end of the output shaft 360 by applying a strong external forceexceeding an anticipated force to the rear wiper, the resin-made bush340 is deformed.

The strong force exceeding an anticipated force is generated when adriver of a vehicle or another person presses the rear wiper in adirection reverse to the swinging direction of rear wiper or waterattached to the rear wiper is frozen to adhere to the rear wiper.

When a strong force crossing in the axial direction acts on the distalend of the output shaft 360, in other words, when a strong bendingmoment acts on the output shaft 360, the resin-made bush 340 supportingthe most base end side of the output shaft 360 is deformed. Therefore,the output shaft 360 can slightly tilt with the sliding bearing 332 as astarting point.

Thus, by supporting the most base end side of the base end portion 362of the output shaft 360 by the resin-made bush 340 having fragility,such a drawback can be prevented that the output shaft 360 bites intothe sliding bearing 332 when a strong external force exceeding ananticipated force is applied to the output shaft 360. The “biting” meansthat the output shaft 360 and the sliding bearing 332 is bonded to eachother in a melting manner.

Even if the output shaft 360 tilts due to a strong bending moment actingthereon, it can continue to rotate without biting into the slidingbearing 332 while deforming the resin-made bush 340.

The conventional electric motor apparatus is configured such that, evenif a strong bending moment has acted on an output shaft, the outputshaft does not tilt. A sliding bearing is formed over an approximatelywhole region of a center hole of a sleeve to receive the strong bendingmoment. Thereby, such a drawback that the output shaft bites into thesliding bearing is prevented. Therefore, according to increase of theentire length of the output shaft, it is necessary to make the entirelength of the sleeve (the sliding bearing) longer.

However, according to increase of the length of the sleeve, it becomesmore difficult to perform a die cutting work of a mold for molding asleeve or a cutting work of a sliding bearing. Furthermore, it isnecessary to use sleeves with different lengths for respective vehicletypes. That is, since it is necessary to prepare different housingscorresponding to vehicle types, reduction of a manufacturing efficiencyand cost rise are incurred.

On the other hand, the electric motor apparatus 301 allows the outputshaft 360 to slightly tilt, when a strong bending moment acts on theoutput shaft 360. The resin-made bush 340 supporting a portion of thebase end portion 362 of the output shaft 360 is deformed so that such adrawback is prevented that the output shaft 360 bites into the slidingbearing 332. Therefore, even if the entire length of the output shaft360 becomes long, it is unnecessary to make the entire length of thesleeve 330 (the sliding bearing 332) long.

Therefore, it can be made easy to perform a die cutting work of a moldmolding the sleeve 330 or a cutting work of the sliding bearing 332.Furthermore, even if the lengths of the output shafts 360 correspondingto respective vehicle types are different, the lengths of the sleevesare the same, so that it is unnecessary to prepare a plurality ofhousings 320. Therefore, improvement of the manufacturing efficiency andthe cost reduction can be achieved.

Lubrication grooves 342 holding lubricant such as grease are formed onthe inner circumferential face of the center hole 341 of the resin-madebush 340. Thereby, the output shaft 360 can be rotated smoothly for along period of time.

Four projecting portions 343 projecting in a diametrical direction areintegrally formed on one end portion of the resin-made bush 340. Thefour projecting portions 343 are arranged at intervals of 90 degrees. Onthe other hand, two recessed portions 334 corresponding to fourprojection portions 343 of the resin-made bush 340 are formed on a backface of the sleeve 330 (the bottom face 332 s of the transmissionmechanism accommodating portion 323) in the accommodating portion 333.One recessed portion 334 corresponds to two projection portions 343.

When the resin-made bush 340 is accommodated in the accommodatingportion 333, four projection portions 343 are fitted into two recessedportions 334 two by two. Thereby, the resin-made bush 340 cannot rotatearound the axial direction to the sleeve 330. That is, the whirl-stopmechanism of the resin-made bush 340 is constituted of four projectionportions 343 of the resin-made bush 340 and two recessed portions 334 ofthe accommodating portion 333.

(Shaft Abutting Portion)

FIG. 32 is a view showing a shaft abutting portion 325. FIG. 32(a) is aplan view, and FIG. 32(b) is a sectional view.

The worm shaft 352 connected to the motor shaft 313 is accommodated inthe transmission mechanism accommodating portion 323 of the housing 320.A base end of the worm shaft 352 (the distal end of the motor shaft 313)is supported by a sliding bearing 322 attached to the housing 320. Onthe other hand, a distal end 352 t of the worm wheel 352 is a free endwhich is not supported by a bearing or the like.

That is, the worm shaft 352 is a cantilever structure where it issupported by only the sliding bearing 322.

The shaft abutting portion 325 provided so as to stand up from thebottom face 323 s of the transmission mechanism accommodating portion323 is provided laterally of the distal end 352 t of the worm shaft 352.The shaft abutting portion (the shaft abutting portion) 325 is providedon the side opposite to the worm wheel 354 regarding the worm shaft 352laterally of the worm shaft 352.

The shaft abutting portion 325 is arranged at a position spaced awayfrom the distal end 352 t of the worm shaft 352 by several millimeters.The shaft abutting portion 352 comes close to the distal end 352 t ofthe worm shaft 352 but it is not in contact with the distal end 352 t.

When the a rotational force of the electric motor section 310 istransmitted from the worm shaft 352 to the worm wheel 354, there is sucha case that the worm shaft 352 is deflected to the opposite side to theworm wheel 354 with a region of the worm shaft 352 supported by thesliding bearing 322 as a starting point.

Thus, when the worm shaft 352 is deflected, the distal end 352 t of theworm shaft 352 abuts on the shaft abutting portion 325. Thereby, whenthe worm shaft 352 is deflected, plastic deformation or a crack isprevented from being generated.

In order to prevent such a drawback, it is thought that aboth-end-support structure where the distal end 352 t of the worm shaft352 is also supported by a bearing is adopted.

However, a troublesome machining work is required in order to form abearing (a sliding bearing) supporting the distal end 352 t of the wormshaft 352.

It is necessary to perform a hole processing to the housing 320 in orderto form a bearing for supporting the worm shaft 352 on the housing 320(the transmission mechanism accommodating portion 323).

Since the sliding bearing 322 is formed on the motor attaching portion321, the hole processing is easy.

On the other hand, a hole processing for forming a bearing forsupporting the distal end 352 t of the worm shaft 352 is performed byinserting a cutting tool from the through-hole causing the motorattaching portion 321 and the transmission mechanism accommodatingportion 323 to communicate with each other and working a wall face orthe like ahead thereof. Thus, since it is necessary to work a narrow andinner region by a slender cutting tool, a troublesome machining workwith a high degree of difficulty is required.

Therefore, by providing the shaft abutting portion 325 provided from thebottom face 323 s of the transmission mechanism accommodating portion323 in a standing manner, the troublesome cutting work (a holeprocessing) with a high degree of difficulty is omitted in the electricmotor apparatus 301.

Since the worm shaft 352 is sufficiently supported by the slidingbearing 322, a frequency of deflection of the worm shaft 352 is reduced.Therefore, by providing the shaft abutting portion 352, such a drawbackas plastic deformation of the worm shaft 352 or crack generation can beprevented.

The shaft abutting portion 325 is formed in a standing manner along adie-cutting direction of the transmission mechanism accommodatingportion 323 of the housing 320. The shaft abutting portion 325 is formedin a standing fashion along a die-cutting direction of a mold (notshown) molding the transmission mechanism accommodating portion 323.That is, the shaft abutting portion 325 is formed in a standing mannervertically from the bottom face 323 s of the transmission mechanismaccommodating portion 323 in an opening direction. Therefore, theabutting portion 325 is formed without causing cost rise.

As described above, in the electric motor apparatus 301, the sleeve 330rotatably supporting the output shaft 360 is provided with the slidingbearing 332 and the resin-made bush 340. Thereby, when a strong bendingmoment acts on the output shaft 360, the resin-made bush 340 is deformedso that such a drawback can be prevented that the output shaft 360 bitesinto the sliding bearing 332.

Since the electric motor apparatus 301 allows the output shaft 360 totilt slightly when the resin-made bush 340 is deformed, even if theentire length of the output shaft 360 is long, it is unnecessary to makethe entire length of the sleeve 330 (the sliding bearing 332) long. Thatis, the sleeve 330 of the electric motor apparatus 301 can supportoutput shafts 360 having various lengths.

Therefore, the die-cutting work of a mold molding the sleeve 330 or thecutting work of the sliding bearing 332 can be made easy. Furthermore,since the lengths of the sleeves 330 are the same, it is unnecessary toprepare a plurality of housings 320, so that improvement of amanufacturing efficiency and cost reduction can be achieved.

Furthermore, the electric motor apparatus 301 is provided with the shaftabutting portion 325 coming in close to the worm shaft 352 supported inthe transmission mechanism accommodating portion 323 in a cantilevermanner. When the worm shaft 353 is deflected, the distal end 352 t ofthe worm shaft 352 abuts on the shaft abutting portion 325, so that sucha drawback as plastic deformation of the worm shaft 352 or a crackgeneration therein can be prevented.

(Modified Examples of Shaft Abutting Portion)

FIG. 33 is a view showing a first modified example (a shaft abuttingportion 0326) of the shaft abutting portion. FIG. 34 is a view showing asecond modified example (a shaft abutting portion 327) of the shaftabutting portion. FIG. 35 is a view showing a third modified example (ashaft abutting portion 328) of the shaft abutting portion.

Instead of the shaft abutting portion 325, either one of the shaftabutting portions 326 to 328 can be used.

The shaft abutting portion (shaft abutting portion) 326 is provided tothe worm shaft 352 laterally of the same side as the worm wheel 354.

There is such a case that the worm shaft 352 is deflected so as to getclose to the worm wheel 354 with a region of the worm shaft 352supported by the sliding bearing 322 as the starting point. The shaftabutting portion 326 provides for such a case.

The shaft abutting portions (shaft abutting portions) 327 are providedto the worm shaft 352 laterally of both the same side as the worm wheel354 and the opposite side thereto, respectively.

There is such a case that the worm shaft 352 is deflected in a directiongetting close to the worm wheel 354 and in a direction departingtherefrom, respectively, with a region of the worm shaft 352 supportedby the sliding bearing 322 as the starting point. The shaft abuttingportions 327 provide for such a case.

The shaft abutting portions (shaft abutting portions) 328 are providedto the worm shaft 352 laterally of both the same side as the worm wheel354 and the opposite side thereto, respectively. Furthermore, the bottomface 323 s of the transmission mechanism accommodating portion 323 isalso formed to get close to the distal end 352 t of the worm shaft 352.That is, the shaft abutting portion 328 is formed so as to have a shape(a semi-circular recessed portion) surrounding the distal end 352 t ofthe worm shaft 352 from three directions.

There is such a case that the worm shaft 352 is deflected in a directiongetting close to the worm wheel 354 and in a direction departingtherefrom, and further in a vertical direction with a region of the wormshaft 352 supported by the sliding bearing 322 as the starting point.The shaft abutting portions 328 provide for such a case.

(Modified Example of Transmission Mechanism)

FIG. 26 is a view showing a modified example (a transmission mechanism3150) of the transmission mechanism.

Instead of the transmission mechanism 350, the transmission mechanism3150 can be used.

The transmission mechanism 3150 is composed of the worm shaft 352, theworm wheel 354, a power transmission member 3156 connected to the wormwheel 354, a coupling plate 3157 connected to the power transmissionmember 3156, and a second sector gear 3158 connected to the couplingplate 3157.

The power transmission member 3156 is formed of a flat plate shapemetal, and it is provided with an elongated plate portion 3156 b, and afan-shaped first sector gear portion 3156 c formed integrally with theplate portion 3156 b.

An end portion 3156 e of the plate portion 3156 b is pivotally connectedto (supported by) a coupling shaft 355 provided on a side face (an upperface) of the worm wheel 354.

The first sector gear portion 3156 c of the power transmission member3156 meshes with the second sector gear 3158.

The second sector gear portion 3158 is formed into a fan shape, and itis arranged outside the worm wheel 354. The output shaft 360 is fixed toa pivoting center of the second sector gear 3158.

A sector gear shaft 3156 d is attached to a pivoting center of the firstsector gear portion 3156 c. An elongated plate-shaped coupling plate3157 is disposed between the sector gear shaft 3156 d and the outputshaft 360.

The coupling plate 3157 is disposed between the sector gear shaft 3156 dand the output shaft 360, so that a distance between the sector gearshaft 3156 d and the output shaft 360 is kept constant.

The coupling shaft 355 is rotationally moved along the circumferentialdirection of the worm wheel 354 according to rotation of the worm wheel354. The power transmission member 3156 and the coupling plate 3157rotatably coupled to each other are swung by the rotational movement ofthe coupling shaft 355. The swinging is continuously repeated accordingto the rotational movement of the coupling shaft 355 such that arelative angle between the power transmission member 3156 and thecoupling plate 3157 increases and decreases. When the coupling shaft 355(the worm wheel 354) rotates one time, a series of movements where therelative angle between the power transmission member 3156 and thecoupling plate 3157 increases and decreases are performed one time.

According to the swinging of the power transmission member 3156 and thecoupling plate 3157, the first sector gear portion 3156 c of the powertransmission member 3156 is pivoted about the sector gear shaft 3156 d.According to the pivoting of the first sector gear portion 3156 c, thesecond sector gear 3158 meshing with the first sector gear portion 3156c and the output shaft 360 are pivoted.

The output shaft 360 is pivoted by one reciprocation according to onerotation of the worm wheel 354 (the coupling shaft 355).

The present invention is not limited to this embodiment, but it goeswithout saying that the present invention can be variously modifiedwithout departing from the gist of the present invention.

The housing 320 is not limited to the case where the transmissionmechanism accommodating portion 323 and the sleeve 330 are formedintegrally with each other. Such a case that the transmission mechanismaccommodating portion 323 and the sleeve 330 are formed individually canbe adopted.

The case where the resin-made bush 340 is used as the second bearing hasbeen described, but this invention is not limited to this case. A bush(bearing) formed of gold, silver, resin or the like can be used as thesecond bearing.

The second bearing is only required to be formed of material weaker inmechanical strength than the first bearing. Therefore, when the firstbearing is formed of iron, a bush (a bearing) formed of copper,aluminum, gold, silver, resin and the like can be used as the secondbearing.

The case where the number of projection portions 343 of the resin-madebush 340 is four, and the number of recessed portions 334 of theaccommodation portion 333 is two has been described, but the presentinvention is not limited to this case. If a structure where theresin-made bush 340 cannot be rotated relative to the accommodatingportion 333 is adopted, the numbers of projection portions 343 andrecessed portions 334 can be set arbitrarily.

The case where the worm shaft 352 and the worm wheel 354 cannot berotated reversely (the case where a self-lock mechanism is provided) hasbeen described, but the present invention is not limited to this case. Acase where the worm shaft 352 and the worm wheel 354 can be rotatedreversely (the case where a self-lock mechanism is not provided) can beadopted.

Seventh Embodiment

Hereinafter, a seventh embodiment of the present invention will bedescribed in detail with reference to the drawings.

FIG. 37 is a plan view of an electric motor apparatus 401 according to aseventh embodiment. FIG. 37 shows it with a housing cover off which willbe described below.

The electric motor apparatus (motor apparatus) 401 is used, for example,as an electric motor apparatus for rear wiper driving (a wiper motor)pivoting a wiper arm such as a rear wiper (not shown). The electricmotor 301 is provided to a back door of a vehicle. A rear wiper (a wiperarm (not shown)) wiping a rear window glass of the vehicle is attachedto an output shaft 460 of the electric motor apparatus 401.

The electric motor apparatus 401 is provided with an electric motorsection (a motor section) 410, a housing 420, a transmission mechanism450, an output shaft 460, and the like.

The electric motor section 410 is a drive source swinging the rearwiper. The housing 420 accommodates the transmission mechanism 450 andsupports the electric motor section 410 and the output shaft 460. Thetransmission mechanism 450 is connected to the electric motor section410 to transmit a rotation force of the electric motor section 410. Theoutput shaft 460 is coupled to the transmission mechanism 450 totransmit the rotation force of the electric motor section 410 to therear wiper.

(Electric Motor Section)

The electric motor section 410 is a so-called “motor with brush”supplying power using a brush.

The electric motor section 410 is provided with a bottomed cylindricalmotor housing 411, an armature (not shown) rotatably arranged within themotor housing 411, and the like.

The motor housing 411 is a member made of metal such as iron, and it isformed by press work for performing deep drawing or the like. Aplurality of magnets is attached to an inner circumferential face of themotor housing 411 by adhesive or the like.

A flange 412 is formed on an opening end of the motor housing 411. Themotor housing 411 is fixed to the housing 420 by bolts inserted intoattaching holes (not shown) of the flange 412.

The armature has a motor shaft 413 and the like. The motor shaft 413 isa rod-shaped member made of metal such as iron. One end (not shown) ofthe motor shaft 413 is supported at a bottom portion of the motorhousing 411. A distal end of the motor shaft 413 is rotatably supportedby the housing 420 through a sliding bearing 422.

(Housing)

The housing 420 is a member made of, for example, aluminum or the like.The housing 420 is formed by aluminum die-casting. The housing 420 has amotor attaching portion 421, a transmission mechanism accommodatingportion 423, and a sleeve 430, which are formed integrally.

The electric motor section 410 is attached to the motor attachingportion 421. The motor attaching portion 421 and the transmissionmechanism accommodating portion 423 communicate with each other througha through-hole (not shown). A motor shaft 413 (a worm shaft 452) isinserted into the through-hole.

A connector member (a connector unit) 470 for supplying power to theelectric motor section 410 is assembled to the motor attaching portion421. A harness (an external connector, not shown) extending from a powersource (not shown) such as a battery is connected to the connectorhousing 470. Thereby, power is supplied to the electric motor section410.

A sliding bearing 422 is formed on the motor attaching portion 421. Thesliding bearing 422 is formed by cutting work. The sliding bearing 422is arranged coaxially with the through-hole causing the motor attachingportion 421 and the transmission mechanism accommodating portion 423 tocommunicate with each other.

The transmission mechanism accommodating portion 423 is a bottomedbox-shaped region whose one face is opened and it accommodates thetransmission mechanism 450. The transmission mechanism 450 is arrangedon a bottom face 423 s of the transmission mechanism accommodatingportion 423. A plate-shaped housing cover (not shown) is attached to anopening of the transmission mechanism accommodating portion 423 to closean internal space of the transmission mechanism accommodating portion423.

The sleeve 430 is a cylindrical region provided on an outer face of thetransmission mechanism accommodating portion 423 in a standing fashion.The sleeve 430 rotatably supports a base end portion 462 of the outputshaft 460.

(Transmission Mechanism)

The transmission mechanism 450 is composed of a worm shaft 452, a wormwheel 454, a power transmission member 456 coupled to the worm wheel454, a coupling plate 457 connected to the power transmission member456, and a second sector gear 458 connected to the coupling plate 457.

The worm shaft 452 is a shaft-shaped screw gear wheel formed at thedistal end of the motor shaft 413. The worm shaft 452 is formedintegrally with the motor shaft 413.

A base end of the worm shaft 452 is rotatably supported to the housing420 via a sliding bearing 422 attached to the housing 420.

The worm wheel (sliding member) 454 is a helical gear, and it isrotatably supported by a center shaft (not shown) provided on a bottomface 423 s of the transmission mechanism accommodating portion 423 in astanding manner. The worm wheel 454 meshes with the worm shaft 452 sothat a rotation force of the electric motor section 410 is transmittedfrom the worm shaft 452 to the worm wheel 454.

A rotation speed of the motor shaft 413 of the electric motor section410 is reduced by the worm shaft 452 and the worm wheel 454. A largespeed reduction ratio can be obtained by the worm shaft 452 and the wormwheel 454. Furthermore, this gear mechanism is smaller in backlash thanthe other gear mechanisms. The worm wheel 454 is rotated according torotation of the worm shaft 452, but the inverse rotation is impossible.

The power transmission member (the sliding member, the both-face slidingmember, the link member) 456 is a member formed into an elongated flatplate shape. The power transmission member 456 is formed by performingpress work to, for example, a high-tension steel (High Tensile StrengthSteel). The power transmission member 456 has an elongated plate portion456 b and a fan-shaped first sector gear portion (a sector gear portion)456 c formed integrally with the plate portion 456 b.

An end portion 456 e of the plate portion 456 b is pivotally connectedto (supported by) the coupling shaft 455 provided on a side face (anupper face) of the worm gear 454.

The first sector gear portion 456 c of the power transmission member 456meshes with the second sector gear 458.

The second sector gear (the sliding member, the sector gear) 458 is agear formed into a fan shape. The second sector gear 258 is formed byperforming press work to, for example, a high-tension steel. The secondsector gear 458 is arranged on the side of an outer circumstance of theworm wheel 454. The output shaft 460 is fixed to the center of thesecond sector gear 458.

The sector gear shaft 456 d is attached to the center of the firstsector gear section 456 c.

The sector gear shaft 456 d and the output shaft 460 are rotatablycoupled with an elongated plate-shaped coupling plate 457 (the slidingmember, the connection sliding member), respectively. The coupling plate457 is formed by performing press work to a high-tension steel.

The coupling plate 457 is disposed between the sector gear shaft 456 dand the output shaft 460, so that a distance between the sector gearshaft 456 d and the output shaft 460 is kept constant.

The worm wheel 454 (the coupling shaft 455), the power transmissionmember 456, the coupling plate 457, and the housing 420 (thetransmission mechanism accommodating portion 423) collectivelyconstitute a four-joint link mechanism.

The coupling shaft 455 is rotationally moved along a circumferentialdirection of the worm wheel 454 according to rotation of the worm wheel454. The power transmission member 456 coupled to the coupling shaft 455swings the coupling plate 457 according to the rotational movement ofthe coupling shaft 455. A motion where a relative angle between thepower transmission member 456 and the coupling plate 457 increases anddecreases is continuously repeated according to the rotational movementof the coupling shaft 455. When the coupling shaft 455 (the worm wheel354) rotates one time, a series of movements where the relative anglebetween the power transmission member 456 and the coupling plate 457increases and decreases are performed one time.

According to the swinging of the power transmission member 456 and thecoupling plate 457, the first sector gear portion 456 c of the powertransmission member 456 is pivoted about the output shaft 460 (thesector gear shaft 456). Thereby, the second sector gear 458 meshing withthe first sector gear portion 456 c and the output shaft 460 arepivoted. The output shaft 460 is pivoted by one reciprocation accordingto one rotation of the worm wheel 454 (the coupling shaft 455).

(Output Shaft)

The output shaft 460 is a rod-shaped member formed of metal such as, forexample, iron. The output shaft 460 is provided toward the outside ofthe housing 420 (the transmission mechanism accommodating portion 423)in a projecting manner.

An entire length of the output shaft 460 varies corresponding to vehicletypes because it is properly set according to a vehicle type on whichthe electric motor apparatus 401 is mounted.

A base end portion 462 of the output shaft 460 is rotatably supported bythe sleeve 430 of the housing 420. A center hole 431 extending along alongitudinal direction is formed in the sleeve 430. The center hole 431communicates with the transmission mechanism accommodating portion 423of the housing 420.

A base end of the output shaft 460 is coupled to the transmissionmechanism 450. The base end of the output shaft 460 is connected to thesecond sector gear 458. The output shaft 460 and the second sector gear458 are fitted to each other, and not rotated with respect to eachother.

A screw portion (not shown) is formed at a distal end of the outputshaft 460. A rear wiper is fixed to the screw portion by a nut or thelike.

The output shaft 460 is pivoted in a reciprocating fashion in responseto swinging of the second sector gear 458. The output shaft 460 ispivoted by one reciprocation for each rotation of the worm wheel 454.The rear wiper attached to the output shaft 460 is swung according tothe reciprocating pivot of the output shaft 460.

(Sliding Member)

FIG. 38 is a sectional view of the transmission mechanism 450.

FIG. 39 is a view showing the coupling plate 457 and the second sectorgear 458, FIG. 39(a) is a plan view of the coupling plate 457, FIG.39(b) is a sectional view of an outer edge of the coupling plate 457,and FIG. 39(c) is a plan view of the second sector gear 458.

The power transmission member 456, the coupling plate 457 and the secondsector gear 458 of members constituting the transmission mechanism 450are members (sliding members) swung or pivoted while they coming insliding contact with (be sliding) one another.

The power transmission member 456, the coupling plate 457 and the secondsector gear 458 are flat plate-shaped members, respectively, and theyare formed by performing press work (punching) to a sheet metal (ahigh-tension steel) with a thickness of about 3 mm or the like.

Therefore, the power transmission member 456, the coupling plate 457 andthe second sector gear 458 have machined faces 456 f, 457 f and 458 f towhich press work is performed and back faces 456 h, 357 h, 358 h facingthe machined faces 456 f, 457 f and 458 f back to back. The machinedfaces 456 f, 457 f and 458 f are faces on which a punch (a male die)abuts and the back faces 456 h, 457 h, 458 h are faces on which a die (afemale die) abuts (is placed), when press work is performed.

When a sheet metal is subjected to press work (punching work), a droop“D” or a burr “B” is formed in a region through which the punch haspassed.

As shown in FIG. 39(b), in the coupling plate 457, for example, a droop“D” and a burr “B” are formed in an inner face of an outer peripheralface orthogonal to the machined face 457 f and the back face 457 h. Theside of the machined face 457 f of the inner face of the outerperipheral face constitutes a sheared face to be formed with the droop“D”. The side of the back face 457 h constitutes a broken face to beformed with the burr “B”. The burr “B” projects on the side of the backface 457 h to be formed in a standing fashion vertically from the backface 457 h.

A droop “D” and a burr “B” are also formed on an inner face of thethrough-hole of the coupling plate 457. When the through-hole is formedsimultaneously with punching the coupling plate 457 from a sheet metal,both of an inner face of a burr “B” formed on an inner face of the outerperipheral face and a burr “B” formed on the through-hole project to theside of the back face 457 h.

In the case where the through-hole is formed after the coupling plate457 has been punched out from the sheet metal, there is such a case thatprojecting directions of the burr “B” formed on the inner face of theouter peripheral face and the burr “B” formed on the inner face of thethrough-hole are reversed to each other.

Similarly, burrs “B” projecting from the back faces 456 h are alsoformed on inner faces of the outer peripheral faces of the powertransmission member 456 and the second sector gear 458.

It is desirable to completely remove the burrs “B” formed on the outerperipheral faces of the power transmission member 456, the couplingplate 457 and the second sector gear 458. However, there is also such acase that a burr-removing work is insufficient or a burr-removing workis not performed.

Incidentally, the burr “B” formed on the inner face of the through-holeis almost completely removed since the shaft or the like is fitted intothe through-hole.

When the transmission mechanism 450 is assembled in such a state thatburrs “B” remain on the outer peripheral faces of the power transmissionmember 456, the coupling plate 457 and the second sector gear 458,drawbacks described below occur.

The power transmission member 456, the coupling plate 457 and the secondsector gear 458 are arranged so as to overlap with one another to comein sliding contact with one another. The power transmission member 456and the coupling plate 457 come in sliding contact with each other, andthe coupling plate 457 and the second sector gear 458 come in slidingcontact with each other.

At this time, for example, when the back face 456 h of the powertransmission member 456 and the back face 457 h of the coupling plate457 come in sliding contact with each other, the burr “B” projectingfrom the back face 456 h and the burr “B” projecting from the back face457 h come in contact with each other so that they bite into each other.The biting means melt-bonding between metals due to frictional heat.Therefore, such a drawback that sliding between the power transmissionmember 456 and the coupling plate 457 is blocked occurs.

Furthermore, there is a possibility that noises are generated due torubbing of burrs “B” against each other or a wear resistance(durability) of the power transmission member 456 or the coupling plate457 lowers.

Therefore, the transmission mechanism 450 of the electric motorapparatus 401 is configures such that burrs “B” formed on the powertransmission member 456, the coupling plate 457 and the second sectorgear 458 do not come in contact with one another.

Specifically, the second sector gear 458 is arranged such that the backface 458 h faces the side of the bottom face 423 s of the transmissionmechanism accommodating portion 423 (the housing 420). Therefore, themachined face 58 f of the second sector gear 58 faces the opening sideto come in sliding contact with the coupling plate 457.

The coupling plate 457 is arranged such that the back face 457 h facesthe opening side. Therefore, the machined face 457 f of the couplingplate 457 faces the side of the bottom face 423 s of the transmissionmechanism accommodating portion 423 (the housing 420) to come in slidingcontact with the second sector gear 458.

Thus, since the coupling plate 457 and the second sector gear 458 isconfigured such that the machined faces 457 f and 458 f come in slidingcontact with each other, the burrs “B” do not come in contact with eachother. Therefore, the coupling plate 457 and the second sector gear 458can slide or pivot smoothly.

The power transmission member 456 is arranged such that the back face456 h faces the opening side. Therefore, the machined face 456 f of thepower transmission member 456 faces the side of the bottom face 423 s ofthe transmission mechanism accommodating portion 423 (the housing 420)to come in sliding contact with the worm wheel 454.

Thus, since the power transmission member 456 causes the machined face456 f to come in sliding contact with the worm wheel 454, the burr “B”is prevented from coming in contact with the side face of the worm wheel454. Therefore, the power transmission member 456 and the worm wheel 454can slide or rotate smoothly.

On the other hand, the back face 456 h of the power transmission member456 comes in sliding contact with the machined face 457 f of thecoupling plate 457. Therefore, the burr “B” of the power transmissionmember 456 comes in contact with the machined face 457 f of the couplingplate 457.

When a sliding movement area of the power transmission member 456 to theworm wheel 454 and a sliding movement area of the power transmissionmember 456 to the coupling plate 457 are compared with each other, theformer (the sliding movement area to the worm wheel 454) is larger thanthe latter several times.

Therefore, by avoiding that the burr “B” of the power transmissionmember 456 comes in contact with the worm wheel 454, the burr “B” isbrought into contact with the coupling plate 457. The burr “B” of theburrs “B” of the power transmission member 456 coming in contact withthe coupling plate 457 is only one formed on the first sector gearportion 456 c. Furthermore, contact between burrs “B” is avoided.Therefore, a possibility of occurrence of a drawback such as describedabove is low.

The coupling plate 457 and the second sector gear 458 can be formed in aline-symmetric shape regarding an imaginary line extending through thethrough-hole or the center hole.

However, when the coupling plate 457 or the second sector gear 458 isformed into a line-symmetric shape, there is such a possibility that anattaching direction of the coupling plate 457 or the second sector gear458 is missed at an assembling time of the transmission mechanism 450.That is, since the machined face 457 f, 458 f and the back face 457 h,458 h cannot be distinguished from each other, there is a possibilitythat the machined face 457 f, 458 f and the back face 457 h, 458 h areassembled to be become opposite to each other. In such a case, theabove-described drawback occurs.

Therefore, as shown in FIG. 39, the coupling plate 457 and the secondsector gear 458 are formed into a non-symmetric shape.

The coupling plate 457 is composed of ring-shaped connecting portions457 s at both ends thereof, and a rectangular central portion 457 tcoupling the connecting portions. Portions at which the connectingportions 457 s and the central portion 457 t connect to each other areformed into a non-symmetric shape.

Incidentally, a sectional area of the central portion 457 t is set tobecome slightly larger than the sectional area of the connecting portion457 s. This is because weight reduction is achieved while strength issecured.

(Sliding Contact Face)

As shown in FIG. 37, a sliding contact face 424 coming in slidingcontact with the power transmission member 456 is formed on the bottomface 423 s of the transmission mechanism accommodating portion 423 (thehousing 420). The sliding contact face 424 is formed on the outercircumferential sides of the worm wheel 454 and the second sector gear458.

When the power transmission member 456 slides so that the first sectorgear portion 456 c of the power transmission member 456 projects fromthe side face (the upper face) of the worm wheel 454 to the outercircumferential side, the machined face 456 f of the power transmissionmember 456 comes in contact with the sliding contact face 424. Thereby,the first sector gear portion 456 c of the power transmission member 456slides while being supported by the sliding contact face 424.

The sliding contact face 242 comes in sliding contact with a region ofthe machined face 456 f of the power transmission member 456 except forthe first sector gear portion 456 c. That is, the sliding contact face424 does not come in sliding contact with a region meshing with thesecond sector gear 458 (the first sector gear portion 456 c) of thedistal end side of the power transmission member 456.

When the first sector gear portion 456 c and the second sector gear 458mesh with each other, sliding contact on the sliding contact face 424causes noises or vibrations. Therefore, the sliding contact face 424 isset so as not to come in sliding contact with the first sector gearportion 456 c.

Furthermore, since the sliding contact face 424 comes in sliding contactwith only a portion of the distal end side of the power transmissionmember 456, a contact area between the power transmission member 456 andthe sliding contact face 424 becomes smaller than that of theconventional art. Therefore, such a drawback that a sliding movement(contact) resistance between the power transmission member 456 and thesliding contact face 424 becomes large, so that sliding movement of thepower transmission member 456 is blocked or the power transmissionmember 456 bits into the sliding contact face 424 is prevented fromoccurring.

Furthermore, a recessed portion (a first recessed portion) 424 g holdinggrease is formed at a central portion of the sliding contact face 424.The grease is held in the recessed portion 424 g, so that the slidingmovement (contact) resistance between the power transmission member 456and the sliding contact face 424 is prevented from increasing.

As described above, in the electric motor apparatus 401, the couplingplate 457 and the second sector gear 458 of the transmission mechanism450 are configured such that the machined face 457 f and 458 f come insliding contact with each other. Therefore, burrs “B” projecting fromthe back faces 457 h and 458 h of the coupling plate 457 and the secondsector gear 458 do not come in contact with each other. Accordingly, thecoupling plate 457 and the second sector gear 458 can slide or pivotsmoothly.

Furthermore, in the electric motor apparatus 401, the machined face 456f of the power transmission member 456 respectively coming in slidingcontact with the coupling plate 457 and the worm wheel 454 is set to theside where the sliding contact area becomes large.

When a sliding movement area of the power transmission member 456 to theworm wheel 454 and a sliding movement area of the power transmissionmember 456 to the coupling plate 457 are compared with each other, theformer is larger than the latter. Therefore, the machined face 456 f ofthe power transmission member 456 is arranged so as to come in slidingcontact with the worm wheel 454.

Therefore, the power transmission member 456 and the worm wheel 454 canslide or rotate smoothly.

On the other hand, since the back face 456 h of the power transmissionmember 456 comes in sliding contact with the machined face 457 f of thecoupling plate 457, the burr “B” of the power transmission member 456comes in contact with the machined face 457 f of the coupling plate 457.However, a portion of the burr “B” of the power transmission member 456only comes in contact with the coupling plate 457. Therefore, such apossibility is low that sliding movement of the power transmissionmember 456 and the coupling plate 457 is blocked.

Furthermore, the coupling plate 457 and the second sector gear 458 areformed into a non-symmetric shape. Therefore, the machined face 456 f,458 f and the back face 457 h, 458 f can be prevented from beingassembled in the opposite directions.

In addition, the sliding contact face 424 coming in sliding contact withthe power transmission member 456 is formed on the bottom face 423 s ofthe transmission mechanism accommodating portion 423 (the housing 420).The sliding contact face 424 does not come in sliding contact with thefirst sector gear portion 456 c at the distal end side of the powertransmission member 456. Therefore, when the first sector gear portion456 c and the second sector gear 458 mesh with each other, it can beavoided that sliding movement on the sliding contact face 424 causesnoises or vibrations.

Furthermore, such a drawback that the sliding movement (contact)resistance between the power transmission member 456 and the slidingcontact face 424 becomes large so that sliding movement of the powertransmission member 456 is blocked or the power transmission member 456bits into the sliding contact face 424 is prevented from occurring.

(Modified Example of Transmission Mechanism)

FIG. 40 is a plan view showing a modified example (a transmissionmechanism 4150) of the transmission mechanism.

FIG. 41 is a sectional view of the transmission mechanism 4150.

The transmission mechanism 4150 can be used instead of the transmissionmechanism 450.

The transmission mechanism 4150 is composed of the worm shaft 452 formedat the distal end of the motor shaft 413, the worm wheel 454 meshingwith the worm shaft 452, a first coupling plate 4156 connected to theworm wheel 454, and a second coupling plate 4158 connected to the firstcoupling plate 4156.

The first coupling plate (the sliding member) 4156 is a member formedinto an elongated flat plate shape. On end side of the first couplingplate 4156 is pivotally connected to (supported by) the coupling shaft455 provided on the side face (the upper face) of the worm wheel 454.

The other end side of the first coupling plate 4156 is pivotallyconnected to (supported by) one end side of the second coupling plate4158.

The second coupling plate (a sliding member) 4158 is a member formedinto a flat plate shape so as to be shorter than the first couplingplate 4156. One end side of the second coupling plate 4158 is pivotallyconnected to (supported by) the other end side of the first couplingplate 4158. The other end side of the second coupling plate 4158 isconnected to the output shaft 460. The second coupling plate 4158 andthe output shaft 460 are connected to each other so as not to be capableof rotating relative to each other.

The output shaft 460 is rotatably supported by the housing 420 (thesleeve 430), so that the other end side of the second coupling plate4158 is also rotatably supported by the housing plate 420.

The worm wheel 454 (the coupling shaft 455), the first coupling plate4156 and the second coupling plate 4158 constitute a four-joint linkmechanism including the housing 420 (the transmission mechanismaccommodating portion 423).

The coupling shaft 455 is rotationally moved along the circumferentialdirection of the worm wheel 454 according to rotation of the worm wheel454. The first coupling plate 4156 coupled to the coupling shaft 455swings the second coupling plate 4158 by the rotational movement of thecoupling shaft 455. Thereby, the output shaft 460 fixed to the secondcoupling plate 4158 is pivoted (pivoted in a reciprocating manner).

The first coupling plate 4156 and the second coupling plate 4158 areformed by performing a press work (a punching) to a sheet metal. Burrs“B” are formed on the back faces 4156 h and 4158 h of the first couplingplate 4156 and the second coupling plate 4158 in a projecting fashion.

The first coupling plate 4156 is arranged such that the back face 4156 hfaces the opening side. Therefore, the machined face 4156 f of the firstcoupling plate 4156 faces the side of the bottom face 423 s of thetransmission mechanism accommodating portion 423 (the housing 420) tocomes in sliding contact with the second coupling plate 4158.

The second coupling plate 4158 is arranged such that the back face 4158h faces the side of the bottom face 423 s of the transmission mechanismaccommodating portion 423 (the housing 420). Therefore, the machinedface 4158 f of the second coupling plate 4158 faces the opening side tocome in sliding contact with the first coupling plate 4156.

Thus, since the first coupling plate 4156 and the second coupling plate4158 are arranged such that the machined faces 4156 f and 4158 f come insliding contact with each other, burrs “B” are prevented from coming incontact with each other. Therefore, the first coupling plate 4156 andthe second coupling plate 4158 can slide or pivot smoothly.

The present invention is not limited to the above embodiments, but itgoes without saying that the present invention can be variously modifiedwithout departing from the gist of the present invention.

The power transmission member 456, the coupling plate 457, the secondsector gear 458, the first coupling plate 4156 and the second couplingplate 4158 are not limited to the case where they are formed by presswork (punching). These members may be formed by laser working. In thiscase, dross pieces are formed on the back face sides of these members ina projecting manner without being formed with the burrs. By preventingthe dross pieces from be brought into contact with each other, the powertransmission member 456 and the like can be slid smoothly.

FIG. 42 is a view showing a recessed portion 456 g of the powertransmission member 456.

The case where the recessed portion 424 g holding grease is formed onthe sliding contact face 424 of the transmission mechanism accommodatingportion 423 (the housing 420) has been described, but the presentinvention is not limited to this case. A recessed portion (a secondrecessed portion) 456 g may be formed on the machined face 456 f of thepower transmission member 456. By causing the recessed portion 456 g tohold grease, the same effect as that of the recessed portion 424 g canbe obtained.

The case where the worm shaft 452 and the worm wheel 454 cannot berotated reversely (the case that a self-lock function is provided) hasbeen described, but the present invention is not limited to this case. Acase where the worm shaft 452 and the worm wheel 454 can be rotatedreversely (a case where the self-lock mechanism is not provided) can beadopted.

The motor apparatus can be used to drive, in a swinging manner, a wiperarm for wiping a window glass provided to an automobile or the like tomake a view of a driver or a person good.

The embodiments described above are provided by way of example only. Theskilled person will be aware of many modifications, changes andsubstitutions that could be made without departing from the scope of thepresent disclosure. The claims of the present disclosure are intended tocover all such modifications, changes and substitutions as fall withinthe spirit and scope of the disclosure.

What is claimed is:
 1. An electric motor comprising a motor case andfour magnets, wherein the motor case has an approximately oval-shapedcross section which has a pair of arc-shaped portions and a pair ofstraight portions, the magnets are housed in the motor case, and fixedalong a circumferential direction of the motor case at intervals of 90degrees.
 2. The electric motor according to claim 1, which is used as adriving source of a wiper apparatus for driving and swinging a wiperblade for wiping a windshield clean.
 3. A motor apparatus provided witha connector unit to which an external connector for supplying drivingcurrent to a motor section is connected, wherein the motor sectioncomprising a motor case and four magnets, wherein the motor case has anapproximately oval-shaped cross section which has a pair of arc-shapedportions and a pair of straight portions, the magnets are housed in themotor case, and fixed along a circumferential direction of the motorcase at intervals of 90 degrees, the connector unit comprises: a baseportion provided with an opening portion in which an armature shaftextending from the motor section is inserted; a connector connectingportion provided with a plug-in hole in which the external connector isplugged; and a plurality of conductive members arranged over the baseportion and the connector connecting portion, wherein the conductivemembers respectively include connector-side connecting portionsconnected to the external connector so as to face the connectorconnecting portion from a first direction reversed to a plug-indirection of the external connector to the plug-in hole, base-sideconnecting portions connected to terminals or wirings provided in thebase portion, and intermediate portions through which the connector-sideconnecting portions and the base-side connecting portions areelectrically connected to each other, wherein the connector-sideconnecting portions of the respective conductive members arerespectively inserted into a plurality of insertion holes provided atpositions different from each other in a second direction intersectingthe first direction, wherein the base-side connecting portions of theconductive members are respectively arranged at the same position in thesecond direction, the intermediate portions of the conductive membersare respectively disposed at positions different from each other in thesecond direction, and the connector unit has supporting faces which aredifferent in position from each other in the second direction, and whichsupport the respective intermediate portions of the conductive members.4. The motor apparatus according to claim 3, wherein a holder memberholding the conductive members is provided between the same and theconnector connecting portion so as to face from the first direction tothe connector connecting portion.
 5. The motor apparatus according toclaim 4, wherein an insulating projection interposed between theconductive members adjacent to each other is formed on an inner face ofthe holder member facing the connector connecting portion.
 6. The motorapparatus according to claim 3, wherein the connector unit is at leastprovided with a first attaching portion attached with a first conductivemember and a second attaching portion attached with a second conducivemember, the first attaching portion has a first supporting face on whicha lower face of the intermediate portion of the first conductive memberis placed, and a first positioning face rising from the first supportingface, on which a side face of the intermediate portion of the firstconductive member is caused to abut, and the second attaching portionhas a second supporting face extending from the first positioning facein parallel with the first supporting face, on which a lower face of theintermediate portion of the second conductive member is placed, and asecond positioning face rising from the second supporting face, on whicha side face of the intermediate portion of the second conductive memberis caused to abut.
 7. The motor apparatus according to claim 3, whereinthe intermediate portions of the conductive members have respective flatportions parallel to the base-side connecting portions, and the flatportions of the intermediate portions are respectively supported by thefirst supporting faces.